Added Python 3 implementation of cmp

Author: domdfcoding

domdf_python_tools/utils.py

@@ -280,3 +280,16 @@ def __contains__(self, key):
 				key = "_False"
 
 		return dict.__contains__(self, key)
+
+
+def cmp(x, y):
+	"""
+	Implementation of cmp for Python 3
+	
+	Compare the two objects x and y and return an integer according to the outcome.
+	The return value is negative if x < y, zero if x == y and strictly positive if x > y.
+
+	:rtype: int
+	"""
+	
+	return int((x > y) - (x < y))