def _filter_language_specific_kwargs(**kwargs):
    """
    Filter out kwargs that aren't actually present

    We want to define all of our possible arguments up front for discoverability by
    users, however some converters would like to specify their own defaults for
    various functions if the kwarg wasn't provided. (e.g. cpp2_srcs, or
    javadeprecated_maven_publisher_version_prefix. So, filter out any of the kwargs
    that are == None (unspecified), and rely on rules to specify their own defaults.
    """

    return {k: v for k, v in kwargs.items() if v != None}