Normalize extensions when loading tool

        """

        Build list of classes for supported data formats

        """

        self.extensions = input_source.get("format", "data").split(",")

        self.extensions = [extension.strip().lower() for extension in input_source.get("format", "data").split(",")]

        formats = []

        if self.datatypes_registry:  # This may be None when self.tool.app is a ValidationContext

            normalized_extensions = [extension.strip().lower() for extension in self.extensions]

            for extension in normalized_extensions:

            for extension in self.extensions:

                datatype = self.datatypes_registry.get_datatype_by_extension(extension)

                if datatype is not None:

                    formats.append(datatype)