check for NoneType in schemas init

[devincowan]

I ran a test script below while looking at hydroshare/hydroshare#4765
Was surprised that a simple file upload gave me an error...
Only my 2nd time using hsclient so maybe it is user error?

import os
from hsclient import HydroShare

hs = HydroShare(host='localhost', protocol="http", port=8000)
hs.sign_in()

# for x in range(0, 100):
new_resource = hs.create()
# Set the Title for the resource
new_resource.metadata.title = 'Res for Testing hs_client file upload'

# Set the Abstract text for the resource
new_resource.metadata.abstract = (
    'Demo for hs_client file upload'
)

# First create a new folder
# new_resource.folder_create('new_folder')

path = 'test_file_upload.txt'
with open(path, 'w') as f:
    f.write('TESTING FILE UPLOAD!')

# Upload one or more files to a specific folder within a resource
# new_resource.file_upload(path, destination_path='new_folder')

# os.remove(path) 

# Print the names of the files in the resource
# print('Updated file list after adding a file: ')
# for file in new_resource.files(search_aggregations=True): 
#   print(file.path)

# Call the save function to save the metadata edits to HydroShare
new_resource.save()

resIdentifier = new_resource.resource_id
existing_resource = hs.resource(resIdentifier)

# First create a new folder
existing_resource.folder_create('new_folder')

# Upload one or more files to a specific folder within a resource
existing_resource.file_upload(path, destination_path='new_folder')

os.remove(path) 

# Print the names of the files in the resource
print('Updated file list after adding a file: ')
for file in existing_resource.files(search_aggregations=True): 
  print(file.path)

# Call the save function to save the metadata edits to HydroShare
existing_resource.save()

Username: admin
Password for admin:
Updated file list after adding a file:
new_folder/test_file_upload.txt
Traceback (most recent call last):
File "/Users/dcowan/repos/hsclient/create_res_upload_file.py", line 54, in
existing_resource.save()
File "/Users/dcowan/repos/hsclient/hsclient/hydroshare.py", line 86, in wrapper
result = f(*args, **kwargs)
File "/Users/dcowan/repos/hsclient/hsclient/hydroshare.py", line 453, in save
metadata_string = rdf_string(self._retrieved_metadata, rdf_format="xml")
File "/Users/dcowan/repos/hsclient/venv/lib/python3.9/site-packages/hsmodels/schemas/init.py", line 91, in rdf_string
return rdf_graph(schema).serialize(format=rdf_format).decode()
File "/Users/dcowan/repos/hsclient/venv/lib/python3.9/site-packages/hsmodels/schemas/init.py", line 87, in rdf_graph
return _rdf_graph(schema, Graph())
File "/Users/dcowan/repos/hsclient/venv/lib/python3.9/site-packages/hsmodels/schemas/init.py", line 110, in _rdf_graph
for f, predicate in _rdf_fields(schema):
File "/Users/dcowan/repos/hsclient/venv/lib/python3.9/site-packages/hsmodels/schemas/init.py", line 95, in _rdf_fields
for f in schema.fields.values():
AttributeError: 'NoneType' object has no attribute 'fields

hsclient v0.3.1
hsmodels v0.5.3