diff --git a/README.md b/README.md
index 18aaf11..aaaa060 100644
--- a/README.md
+++ b/README.md
@@ -130,3 +130,24 @@ def multiples(s1, s2, s3):
     return [a for a in xrange(1, s3) if not(a % s1 or a % s2)]
 ```
 
+Sum of the first nth terms of a series (7 kyu)
+- Module: series_sum.py
+- Tests: test_series_sum.py
+- Link: http://www.codewars.com/kata/sum-of-the-first-nth-term-of-series/train/python
+- Interesting Solution: Making the numerator a float() was smart.
+```python
+def series_sum(n):
+    """Solution by MMMAAANNN"""
+    return '{:.2f}'.format(sum(1.0/(3 * i + 1) for i in range(n)))
+```
+
+
+Proper Parenthetics
+- Module: proper_parenthetics.py
+- Tests: test_proper_parenthetics.py
+
+
+Sort Cards (7kyu)
+-Module: sort_cards.py
+-Tests: test_sort_cards.py
+-Link: https://www.codewars.com/kata/sort-deck-of-cards/train/python
diff --git a/setup.py b/setup.py
index cd6801e..b669148 100644
--- a/setup.py
+++ b/setup.py
@@ -13,7 +13,8 @@
     py_modules=["last", "string_to_array", "fake_binary",
                 "count_positives_sum_negatives", "digitize",
                 "binary_list_to_number", "sea_sick", "reverse_and_mirror",
-                "flatten_me", "sum_from_string", "multiples"],
+                "flatten_me", "sum_from_string", "multiples", "sort_cards",
+                "priority"],
     install_requires=[],
     extras_require={
         "test": ["pytest", "pytest-watch", "pytest-cov", "tox"]
diff --git a/src/__pycache__/test_binary_list_to_number.cpython-27-PYTEST.pyc b/src/__pycache__/test_binary_list_to_number.cpython-27-PYTEST.pyc
index 15650ed..21ab5d0 100644
Binary files a/src/__pycache__/test_binary_list_to_number.cpython-27-PYTEST.pyc and b/src/__pycache__/test_binary_list_to_number.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_count_positives_sum_negatives.cpython-27-PYTEST.pyc b/src/__pycache__/test_count_positives_sum_negatives.cpython-27-PYTEST.pyc
index 88dffe1..16e814e 100644
Binary files a/src/__pycache__/test_count_positives_sum_negatives.cpython-27-PYTEST.pyc and b/src/__pycache__/test_count_positives_sum_negatives.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_digitize.cpython-27-PYTEST.pyc b/src/__pycache__/test_digitize.cpython-27-PYTEST.pyc
index ee8ecb2..4e8759e 100644
Binary files a/src/__pycache__/test_digitize.cpython-27-PYTEST.pyc and b/src/__pycache__/test_digitize.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_fake_bin.cpython-27-PYTEST.pyc b/src/__pycache__/test_fake_bin.cpython-27-PYTEST.pyc
index 88d45bb..d663fde 100644
Binary files a/src/__pycache__/test_fake_bin.cpython-27-PYTEST.pyc and b/src/__pycache__/test_fake_bin.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_flatten_me.cpython-27-PYTEST.pyc b/src/__pycache__/test_flatten_me.cpython-27-PYTEST.pyc
index 3ef8748..a52b673 100644
Binary files a/src/__pycache__/test_flatten_me.cpython-27-PYTEST.pyc and b/src/__pycache__/test_flatten_me.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_last.cpython-27-PYTEST.pyc b/src/__pycache__/test_last.cpython-27-PYTEST.pyc
index 3360ba5..b181a03 100644
Binary files a/src/__pycache__/test_last.cpython-27-PYTEST.pyc and b/src/__pycache__/test_last.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_multiples.cpython-27-PYTEST.pyc b/src/__pycache__/test_multiples.cpython-27-PYTEST.pyc
index 812ac41..e2c8b29 100644
Binary files a/src/__pycache__/test_multiples.cpython-27-PYTEST.pyc and b/src/__pycache__/test_multiples.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_reverse_and_mirror.cpython-27-PYTEST.pyc b/src/__pycache__/test_reverse_and_mirror.cpython-27-PYTEST.pyc
index 05ffc74..d3d7d64 100644
Binary files a/src/__pycache__/test_reverse_and_mirror.cpython-27-PYTEST.pyc and b/src/__pycache__/test_reverse_and_mirror.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_sea_sick.cpython-27-PYTEST.pyc b/src/__pycache__/test_sea_sick.cpython-27-PYTEST.pyc
index c775ca4..f0292be 100644
Binary files a/src/__pycache__/test_sea_sick.cpython-27-PYTEST.pyc and b/src/__pycache__/test_sea_sick.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_string_to_array.cpython-27-PYTEST.pyc b/src/__pycache__/test_string_to_array.cpython-27-PYTEST.pyc
index 36ad973..3116dd3 100644
Binary files a/src/__pycache__/test_string_to_array.cpython-27-PYTEST.pyc and b/src/__pycache__/test_string_to_array.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_sum.cpython-27-PYTEST.pyc b/src/__pycache__/test_sum.cpython-27-PYTEST.pyc
index 7a0308d..1b14d6b 100644
Binary files a/src/__pycache__/test_sum.cpython-27-PYTEST.pyc and b/src/__pycache__/test_sum.cpython-27-PYTEST.pyc differ
diff --git a/src/__pycache__/test_sum_from_string.cpython-27-PYTEST.pyc b/src/__pycache__/test_sum_from_string.cpython-27-PYTEST.pyc
index ab6449a..72c1e50 100644
Binary files a/src/__pycache__/test_sum_from_string.cpython-27-PYTEST.pyc and b/src/__pycache__/test_sum_from_string.cpython-27-PYTEST.pyc differ
diff --git a/src/binary_list_to_number.pyc b/src/binary_list_to_number.pyc
index 65ecd78..676595a 100644
Binary files a/src/binary_list_to_number.pyc and b/src/binary_list_to_number.pyc differ
diff --git a/src/code_katas.egg-info/SOURCES.txt b/src/code_katas.egg-info/SOURCES.txt
index c18a04c..81c3bbc 100644
--- a/src/code_katas.egg-info/SOURCES.txt
+++ b/src/code_katas.egg-info/SOURCES.txt
@@ -5,8 +5,10 @@ src/digitize.py
 src/flatten_me.py
 src/last.py
 src/multiples.py
+src/priority.py
 src/reverse_and_mirror.py
 src/sea_sick.py
+src/sort_cards.py
 src/string_to_array.py
 src/sum_from_string.py
 src/code_katas.egg-info/PKG-INFO
diff --git a/src/code_katas.egg-info/top_level.txt b/src/code_katas.egg-info/top_level.txt
index 4429a32..2b582bf 100644
--- a/src/code_katas.egg-info/top_level.txt
+++ b/src/code_katas.egg-info/top_level.txt
@@ -5,7 +5,9 @@ fake_binary
 flatten_me
 last
 multiples
+priority
 reverse_and_mirror
 sea_sick
+sort_cards
 string_to_array
 sum_from_string
diff --git a/src/count_positives_sum_negatives.pyc b/src/count_positives_sum_negatives.pyc
index 5ff6119..2232787 100644
Binary files a/src/count_positives_sum_negatives.pyc and b/src/count_positives_sum_negatives.pyc differ
diff --git a/src/digitize.pyc b/src/digitize.pyc
index 5570438..ff34534 100644
Binary files a/src/digitize.pyc and b/src/digitize.pyc differ
diff --git a/src/fake_bin.pyc b/src/fake_bin.pyc
index 4bb5359..eaf245f 100644
Binary files a/src/fake_bin.pyc and b/src/fake_bin.pyc differ
diff --git a/src/flatten_me.pyc b/src/flatten_me.pyc
index 74e8866..3bf2f48 100644
Binary files a/src/flatten_me.pyc and b/src/flatten_me.pyc differ
diff --git a/src/last.pyc b/src/last.pyc
index d32bfa8..1cf7697 100644
Binary files a/src/last.pyc and b/src/last.pyc differ
diff --git a/src/linked_list.py b/src/linked_list.py
new file mode 100644
index 0000000..af36cc5
--- /dev/null
+++ b/src/linked_list.py
@@ -0,0 +1,83 @@
+"""Implementation of Linked_List data type."""
+
+
+class LinkedList(object):
+    """Class representation of linked list."""
+
+    def __init__(self, iterable=None):
+        """Instantiate linked list."""
+        self.head_node = None
+        self.length = 0
+        try:
+            for item in iterable:
+                self.push(item)
+        except TypeError:
+            if iterable:
+                return "Please only enter iterable values"
+
+    def push(self, contents):
+        """Add node to this linked list."""
+        self.head_node = Node(contents, self.head_node)
+        self.length += 1
+
+    def pop(self):
+        """Remove and return the current head node."""
+        if not self.head_node:
+            return "Linked list is already empty"
+        old_head_node = self.head_node
+        self.head_node = self.head_node.next_node
+        self.length -= 1
+        return old_head_node.contents
+
+    def size(self):
+        """Return the current size of this linked list."""
+        return self.length
+
+    def search(self, search_value):
+        """Return the node with the searched contents if found."""
+        if self.length:
+            if search_value == self.head_node.contents:
+                return self.head_node
+            current_node = self.head_node
+            while current_node.contents != search_value:
+                if current_node.next_node is None:
+                    return None
+                current_node = current_node.next_node
+            return current_node
+        else:
+            return None
+
+    def remove(self, remove_node):
+        """Remove a node from linked list."""
+        if remove_node == self.head_node:
+            self.head_node = self.head_node.next_node
+            self.length -= 1
+            return None
+        elif remove_node is None:
+            raise ValueError("Provided value not in list.")
+        current_node = self.head_node
+        while current_node.next_node != remove_node:
+            current_node = current_node.next_node
+        current_node.next_node = current_node.next_node.next_node
+        self.length -= 1
+
+    def display(self):
+        """Return the tuple of all values in linked list."""
+        if self.length == 0:
+            return None
+        else:
+            new_list = [self.head_node.contents]
+            current_node = self.head_node
+            while current_node.next_node is not None:
+                current_node = current_node.next_node
+                new_list.append(current_node.contents)
+            return tuple(new_list)
+
+
+class Node(object):
+    """Class representation of linked list node."""
+
+    def __init__(self, contents, next_node):
+        """Instantiate linked list node."""
+        self.contents = contents
+        self.next_node = next_node
diff --git a/src/multiples.pyc b/src/multiples.pyc
index 1716616..cdf71a6 100644
Binary files a/src/multiples.pyc and b/src/multiples.pyc differ
diff --git a/src/priority.py b/src/priority.py
new file mode 100644
index 0000000..10d6cae
--- /dev/null
+++ b/src/priority.py
@@ -0,0 +1,40 @@
+"""Priority Queue data structure."""
+
+
+class PriorityQueue(object):
+    """Priority Queue data structure.
+
+    .insert(item) - adds an item to the queue and sorts
+    .pop() - removes the highest priority item, returns its value.
+    .peek() - returns the value of the highest priority item.
+    """
+
+    def __init__(self, iterable=None):
+        """Initialize the Priority Queue."""
+        self._pq_dict = {}
+        if hasattr(iterable, "__iter__"):
+            for val in iterable:
+                self.insert(val[1], priority=val[0])
+
+    def insert(self, value, priority=0):
+        """Insert values and priorities in to priority queue."""
+        if priority not in self._pq_dict.keys():
+            self._pq_dict[priority] = []
+        self._pq_dict[priority].append(value)
+
+    def pop(self):
+        """Remove the highest priority item, returns its value."""
+        pop_val = self.peek()
+        hi_pri = sorted(self._pq_dict.keys())[0]
+        if len(self._pq_dict[hi_pri]) == 1:
+            del self._pq_dict[hi_pri]
+        else:
+            self._pq_dict[hi_pri] = self._pq_dict[hi_pri][1:]
+        return pop_val
+
+    def peek(self):
+        if len(self._pq_dict.keys()) == 0:
+            raise KeyError("The Priority Queue is empty.")
+        hi_pri = sorted(self._pq_dict.keys())[0]
+        pop_val = self._pq_dict[hi_pri][0]
+        return pop_val
diff --git a/src/proper_parenthetics.py b/src/proper_parenthetics.py
new file mode 100644
index 0000000..aaeff61
--- /dev/null
+++ b/src/proper_parenthetics.py
@@ -0,0 +1,18 @@
+"""Ensure the same number of opening and closing parenthetics in a string."""
+
+from stack import Stack
+
+
+def proper_parenthetics(input_string):
+    """Ensure the balance of opening and closing parenthtics."""
+    parenthetics_stack = Stack()
+    for i in input_string:
+        if i == '(':
+            parenthetics_stack.push(i)
+        if i == ')':
+            if parenthetics_stack.head_node is None:
+                return -1
+            parenthetics_stack.pop()
+    if parenthetics_stack.head_node is None:
+        return 0
+    return 1
diff --git a/src/reverse_and_mirror.pyc b/src/reverse_and_mirror.pyc
index 99b801a..c21cbb1 100644
Binary files a/src/reverse_and_mirror.pyc and b/src/reverse_and_mirror.pyc differ
diff --git a/src/sea_sick.pyc b/src/sea_sick.pyc
index 25b92c7..a146356 100644
Binary files a/src/sea_sick.pyc and b/src/sea_sick.pyc differ
diff --git a/src/sort_cards.py b/src/sort_cards.py
new file mode 100644
index 0000000..de248f8
--- /dev/null
+++ b/src/sort_cards.py
@@ -0,0 +1,49 @@
+"""Sort a deck of cards code-kata using a Priority Queue."""
+
+from priority import PriorityQueue
+
+card_dict = {
+    'A': 1,
+    'T': 10,
+    'J': 11,
+    'Q': 12,
+    'K': 13,
+    1: 'A',
+    10: 'T',
+    11: 'J',
+    12: 'Q',
+    13: 'K',
+}
+
+
+def sort_cards(cards):
+    """Sort shuffled list of cards, sorted by rank."""
+    card_list = []
+    for card in cards:
+        try:
+            card_list.append(int(card))
+        except ValueError:
+            card_list.append(card_dict[card])
+    card_list.sort()
+    result = []
+    for card in card_list:
+        if card > 1 and card < 10:
+            result.append(str(card))
+        else:
+            result.append(card_dict[card])
+    return result
+
+
+def sort_cards_w_pq(cards):
+    """Sort shuffled list of cards, sorted by rank, using a priority queue."""
+    card_list = []
+    for card in cards:
+        try:
+            card_list.append((int(card), card))
+        except ValueError:
+            card_list.append(card_dict[card])
+    card_q = PriorityQueue(card_list)
+    result = []
+    for i in range(len(card_list)):
+        result.append(card_q.pop())
+    return result
diff --git a/src/stack.py b/src/stack.py
new file mode 100644
index 0000000..7c6e988
--- /dev/null
+++ b/src/stack.py
@@ -0,0 +1,24 @@
+"""Implementation of Stack data type."""
+
+from linked_list import LinkedList
+
+
+class Stack(object):
+    """Class representation of a stack."""
+
+    def __init__(self, iterable=None):
+        """Instantiate stack."""
+        self.linked_list = LinkedList(iterable)
+        self.length = self.linked_list.length
+        self.head_node = self.linked_list.head_node
+
+    def push(self, contents):
+        """Add node to this stack."""
+        self.linked_list.push(contents)
+        self.head_node = self.linked_list.head_node
+
+    def pop(self):
+        """Remove and return the current head node."""
+        old_head_node_value = self.linked_list.pop()
+        self.head_node = self.linked_list.head_node
+        return old_head_node_value
diff --git a/src/string_to_array.pyc b/src/string_to_array.pyc
index fd38868..8dccd68 100644
Binary files a/src/string_to_array.pyc and b/src/string_to_array.pyc differ
diff --git a/src/sum_from_string.pyc b/src/sum_from_string.pyc
index c3fa60c..6fa762d 100644
Binary files a/src/sum_from_string.pyc and b/src/sum_from_string.pyc differ
diff --git a/src/test_priority.py b/src/test_priority.py
new file mode 100644
index 0000000..78b30a7
--- /dev/null
+++ b/src/test_priority.py
@@ -0,0 +1,69 @@
+"""Test the priority queue's functionality."""
+
+
+import pytest
+
+INPUT_VALUES = [
+    ([], {}, None, None),
+    ([(1, 'a'), (2, 'b'), (3, 'c')], {1: ['a'], 2: ['b'], 3: ['c']}, 'a', 1),
+    ([(2, 'a'), (5, 'b'), (12, 'c')], {2: ['a'], 5: ['b'], 12: ['c']}, 'a', 2),
+    ([(15, 'words'), (6, 'are'), (70, 'hard')], {6: ['are'], 15: ['words'], 70: ['hard']}, 'are', 6),
+    ([(1, 15), (2, 20), (3, 25)], {1: [15], 2: [20], 3: [25]}, 15, 1),
+    ([(1, 'a'), (1, 'b'), (2, 'c')], {1: ['a', 'b'], 2: ['c']}, 'a', 1),
+]
+
+
+@pytest.fixture(scope="module", params=INPUT_VALUES)
+def pri(request):
+    """Paramaterized fixture for testing."""
+    from priority import PriorityQueue
+    processed = PriorityQueue(request.param[0])
+    prioq = (processed, request.param[1], request.param[2], request.param[3])
+    return prioq
+
+
+def test_init(pri):
+    """Test that the class initializes."""
+    from priority import PriorityQueue
+    assert isinstance(pri[0], PriorityQueue)
+
+
+def test_insert(pri):
+    """Test that values are inserted at the right priority in the right order."""
+    assert pri[0]._pq_dict == pri[1]
+    # (the_input, the_expected_output) = pri
+
+
+def test_pop(pri):
+    """Test that pop returns the right value."""
+    try:
+        assert pri[0].pop() == pri[2]
+    except KeyError:
+        assert True
+
+
+def test_del(pri):
+    """Test that empty keys are deleted."""
+    try:
+        pri[0].pop()
+        pri[0].pop()
+        assert pri[3] not in pri[0]._pq_dict
+    except KeyError:
+        assert True
+
+
+def test_pop_remove(pri):
+    """Test that pop properly removes values."""
+    try:
+        pri[0].pop()
+        assert pri[2] not in pri[0]._pq_dict[pri[3]]
+    except KeyError:
+        assert True
+
+
+def test_peek(pri):
+    """Test that peek returns the right value."""
+    try:
+        assert pri[0].peek() == pri[2]
+    except KeyError:
+        assert True
diff --git a/src/test_proper_parenthetics.py b/src/test_proper_parenthetics.py
new file mode 100644
index 0000000..2099a88
--- /dev/null
+++ b/src/test_proper_parenthetics.py
@@ -0,0 +1,21 @@
+"""Tests for proper_parenthetics."""
+import pytest
+
+
+ASSERTIONS = [
+    ['(', 1],
+    ['(This is (a string)', 1],
+    ['()', 0],
+    ['some (strings) and (others)', 0],
+    ['((Nestes)ones)', 0],
+    [')', -1],
+    ['(bloop))', -1],
+    [')its backwards(', -1]
+]
+
+
+@pytest.mark.parametrize("input, result", ASSERTIONS)
+def test_proper_parenthetics(input, result):
+    """Test proper_parenthetics for proper output in test cases."""
+    from proper_parenthetics import proper_parenthetics
+    assert proper_parenthetics(input) == result
diff --git a/src/test_sort_cards.py b/src/test_sort_cards.py
new file mode 100644
index 0000000..6517f2a
--- /dev/null
+++ b/src/test_sort_cards.py
@@ -0,0 +1,26 @@
+"""Tests for count_positives_sum_negatives.count_positives_sum_negatives."""
+import pytest
+
+
+ASSERTIONS = [
+    [list('39A5T824Q7J6K'), list('A23456789TJQK')],
+    [list('Q286JK395A47T'), list('A23456789TJQK')],
+    [list('54TQKJ69327A8'), list('A23456789TJQK')],
+    [list('AAA4555336773'), list('AAA3334555677')],
+    [list('3'), list('3')],
+    [list('TTTTTTTTTTTAK'), list('ATTTTTTTTTTTK')],
+]
+
+
+@pytest.mark.parametrize("n, result", ASSERTIONS)
+def test_sort_cards(n, result):
+    """Test sort_cards() for proper output in test cases."""
+    from sort_cards import sort_cards
+    assert sort_cards(n) == result
+
+
+@pytest.mark.parametrize("n, result", ASSERTIONS)
+def test_sort_cards_w_pq(n, result):
+    """Test sort_cards_w_pq() for proper output in test cases."""
+    from sort_cards import sort_cards
+    assert sort_cards(n) == result