+
+ # Try one of the format functions
+ if data and type(data) is not dict and a not in data:
+ raise ValueError("Invalid argument: {} expected {}.{}".
+ format(data, self.name, a))
+
+ # Defaulting to zero.
+ if not data or a not in data: # Default to 0
+ arg = None
+ kwarg = None # No default for VLA
+ else:
+ arg = data[a]
+ kwarg = kwargs[a] if a in kwargs else None