def update_default(self, new_default, respect_none=False):
if new_default is not None:<EOL><INDENT>self.default = new_default<EOL><DEDENT>elif new_default is None and respect_none:<EOL><INDENT>self.default = None<EOL><DEDENT>
Update our current default with the new_default.

        Args:
            new_default: New default to set.
            respect_none: Flag to determine if ``None`` is a valid value.