Return whether the cache contains a schema for the input key, sequence number, or schema identifier.

        :param index: schema key, sequence number, or sequence identifier
        :return: whether the cache contains a schema for the input index

def contains(self, index: Union[SchemaKey, int, str]) -> bool:
        """
        Return whether the cache contains a schema for the input key, sequence number, or schema identifier.

        :param index: schema key, sequence number, or sequence identifier
        :return: whether the cache contains a schema for the input index
        """

        LOGGER.debug('SchemaCache.contains >>> index: %s', index)

        rv = None
        if isinstance(index, SchemaKey):
            rv = (index in self._schema_key2schema)
        elif isinstance(index, int) or (isinstance(index, str) and ':2:' not in index):
            rv = (int(index) in self._seq_no2schema_key)
        elif isinstance(index, str):
            rv = (schema_key(index) in self._schema_key2schema)
        else:
            rv = False

        LOGGER.debug('SchemaCache.contains <<< %s', rv)
        return rv