def __call__(self, systemConfig):
for key in self.required:<EOL><INDENT>if key not in systemConfig:<EOL><INDENT>raise ValueError('<STR_LIT>'.format(cls.__name__, key))<EOL><DEDENT><DEDENT>return {key: systemConfig[key] for key in set.union(self.required, self.optional) if key in systemConfig}<EOL>
Args:
    systemConfig (dict): A systemConfig dictionary to filter

Returns:
    dict: Filtered dictionary

Raises:
    ValueError: If a required key is not in the systemConfig