def contains(self, index: Union[SchemaKey, int, str]) -> bool:
LOGGER.debug('<STR_LIT>', index)<EOL>rv = None<EOL>if isinstance(index, SchemaKey):<EOL><INDENT>rv = (index in self._schema_key2schema)<EOL><DEDENT>elif isinstance(index, int) or (isinstance(index, str) and '<STR_LIT>' not in index):<EOL><INDENT>rv = (int(index) in self._seq_no2schema_key)<EOL><DEDENT>elif isinstance(index, str):<EOL><INDENT>rv = (schema_key(index) in self._schema_key2schema)<EOL><DEDENT>else:<EOL><INDENT>rv = False<EOL><DEDENT>LOGGER.debug('<STR_LIT>', rv)<EOL>return rv<EOL>
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