Refactor code for consistency and readability

- Standardized string quotes across multiple files to use double quotes for consistency.
- Improved formatting of JSON dumps in mock data for better readability.
- Enhanced the structure of various functions and data definitions for clarity.
- Updated test cases to reflect changes in data structure and ensure accuracy.

manage.py

@@ -1,12 +1,13 @@
 #!/usr/bin/env python
 """Django's command-line utility for administrative tasks."""
+
 import os
 import sys
 
 
 def main():
     """Run administrative tasks."""
-    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'watcher_visio.settings')
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "watcher_visio.settings")
     try:
         from django.core.management import execute_from_command_line
     except ImportError as exc:
@@ -18,5 +19,5 @@ def main():
     execute_from_command_line(sys.argv)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()