chore: add docstring

src/py/mat3ra/made/tools/build/slab/__init__.py

@@ -16,7 +16,17 @@ def create_slab(configuration: SlabConfiguration, termination: Optional[Terminat
     return builder.get_material(configuration, selector_parameters=SlabSelectorParameters(termination=termination))
 
 
-def create_slab_if_not(material: Material, default_slab_configuration: SlabConfiguration):
+def create_slab_if_not(material: Material, default_slab_configuration: SlabConfiguration) -> Material:
+    """
+    Create a slab from the material if it is not a slab already. Otherwise, return the material.
+
+    Args:
+        material (Material): The material to be checked.
+        default_slab_configuration (SlabConfiguration): The default configuration to be used for creating a new slab.
+
+    Returns:
+        Material: The slab.
+    """
     slab = material
     if not slab.metadata or slab.metadata["build"]["configuration"]["type"] != SlabConfiguration.__name__:
         print("The material is not a slab. Creating a new slab...")