Resolve "Fix mypy errors in models.py and complete type hints"

Summary

This MR fixes many type errors in models.py reported by mypy (Related to #191 (closed))

Focus

• Potential Nones are now handled wherever mypy reported them
• Please check the correctness of IMPORTANCE vs INHERITANCE (see also server docs)
• New type hints for Query, QueryTemplate
• Two open issue remain (see below).

Test Environment

Regular

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related issues
• Up-to-date CHANGELOG.md (or not necessary)
• Up-to-date JSON schema (or not necessary)
• Appropriate user and developer documentation (or not necessary)
  • How do I use the software? Assume "stupid" users.
  • How do I develop or debug the software? Assume novice developers.
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
• Appropriate user and developer documentation (or not necessary)
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

src/linkahead/common/models.py

@@ -2368,13 +2368,13 @@ class _Properties(list):
 
     def __init__(self):
         list.__init__(self)
-        self._importance: Dict[Property, IMPORTANCE] = dict()
-        self._inheritance: Dict[Property, INHERITANCE] = dict()
-        self._element_by_name: Dict[str, Property] = dict()
-        self._element_by_id: Dict[str, Property] = dict()
+        self._importance: Dict[Entity, IMPORTANCE] = dict()
+        self._inheritance: Dict[Entity, INHERITANCE] = dict()
+        self._element_by_name: Dict[str, Entity] = dict()
+        self._element_by_id: Dict[str, Entity] = dict()
 
     def get_importance(
-        self, property: Union[Property, str, None]
+        self, property: Union[Property, Entity, str, None]
     ):  # @ReservedAssignment
         if property is not None:
             if isinstance(property, str):
@@ -2386,7 +2386,7 @@ class _Properties(list):
         if property is not None:
             self._importance[property] = importance
 
-    def get_by_name(self, name: str) -> Property:
+    def get_by_name(self, name: str) -> Entity:
         """Get a property of this list via it's name. Raises a LinkAheadException
         if not exactly one property has this name.
 
@@ -2420,7 +2420,7 @@ class _Properties(list):
             if inheritance is not None:
                 self._inheritance[property] = inheritance
             else:
-                self._inheritance[property] = FIX
+                self._inheritance[property] = "ALL"
 
             if property.id is not None:
                 self._element_by_id[str(property.id)] = property
@@ -3492,7 +3492,7 @@ class Container(list):
                 sync_remote_entities.append(remote_entity)
 
         if len(sync_remote_entities) > 0:
-            sync_dict[self] = sync_remote_entities
+            sync_dict[self] = sync_remote_entities # FIXME: How is this supposed to work?
 
         if unique and len(sync_remote_entities) != 0:
             msg = "Request was not unique. There are " + \
@@ -4686,7 +4686,8 @@ class Query():
         self.etag = None
 
         if isinstance(q, etree._Element):
-            self.q = q.get("string")
+            string = q.get("string")
+            self.q = string if string is not None else ""
             results = q.get("results")
             if results is None:
                 raise LinkAheadException(
@@ -5119,7 +5120,7 @@ def _parse_single_xml_element(elem: etree._Element):
         )
 
 
-def _evaluate_and_add_error(parent_error: TransactionError, ent: Union[Entity, Container]):
+def _evaluate_and_add_error(parent_error: TransactionError, ent: Union[Entity, QueryTemplate, Container]):
     """Evaluate the error message(s) attached to entity and add a
     corresponding exception to parent_error.
 
@@ -5128,7 +5129,7 @@ def _evaluate_and_add_error(parent_error: TransactionError, ent: Union[Entity, C
     parent_error : TransactionError
         Parent error to which the new exception will be attached. This
         exception will be a direct child.
-    ent : Entity or Container
+    ent : Entity or Container or QueryTemplate
         Entity that caused the TransactionError. An exception is
         created depending on its error message(s).