Add 'contains' predicate method (#52)

- Introduced a new predicate for checking if a parameter value contains a substring.
- Added the corresponding method to handle the logic and error management.

src/predicates.py

@@ -16,4 +16,5 @@ PREDICATE_METHOD_MAP = {
     "is like": PropertyRules.is_parameter_value_like.__name__,
     "identical to": PropertyRules.is_identical_value.__name__,
     "not equal": PropertyRules.is_not_equal_value.__name__,
+    "contains": PropertyRules.is_parameter_value_containing.__name__,
 }

src/rules.py

@@ -60,6 +60,31 @@ class Rules:
 class PropertyRules:
     """A collection of rules for processing parameters in Speckle objects."""
 
+    @staticmethod
+    def is_parameter_value_contains(speckle_object: Base, parameter_name: str, substring: str) -> bool:
+        """Checks if parameter value contains the given substring.
+
+        Args:
+            speckle_object: The Speckle object to check
+            parameter_name: Name of the parameter to check
+            substring: The substring to look for
+
+        Returns:
+            bool: True if the parameter value contains the substring
+        """
+        parameter_value = PropertyRules.get_parameter_value(speckle_object, parameter_name)
+        if parameter_value is None:
+            return False
+
+        # Convert both to strings for comparison
+        try:
+            parameter_str = str(parameter_value).lower()
+            substring_str = str(substring).lower()
+            return substring_str in parameter_str
+        except (TypeError, ValueError) as e:
+            print(f"Error in is_parameter_value_contains: {e}")
+            return False
+
     @staticmethod
     def normalize_path(path: str) -> str:
         """Remove technical path prefixes like 'properties' and 'parameters'."""