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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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