diff --git a/map2map/main.py b/map2map/main.py
index 03a10cb..63782f0 100644
--- a/map2map/main.py
+++ b/map2map/main.py
@@ -28,6 +28,18 @@ def _int_tuple(value):
     return t
 
 class VariadicType(click.ParamType):
+    """
+    A custom parameter type for Click command-line interface.
+
+    This class provides a way to define custom parameter types for Click commands.
+    It supports various types such as string, integer, float, JSON, and file paths.
+
+    Args:
+        typename (str or dict): The name of the type or a dictionary specifying the type and options.
+
+    Raises:
+        ValueError: If the typename is not recognized.
+    """
 
     _mapper = {
         "str_list": {"type": "string_list", "func": _str_list},
@@ -58,7 +70,6 @@ class VariadicType(click.ParamType):
         except Exception as e:
             self.fail(f"Could not parse {self._typename}: {e}", param, ctx)
 
-
 def _apply_options(options_file, f):
     common_args = yaml.load(_load_resource_file(options_file), Loader=Loader)
     common_args = common_args['arguments']