MetadataMapping(column_family: 'str', column_name: 'str', metadata_key: 'str', encoding: 'Encoding', custom_encoding_func: 'Callable[[Any], bytes]' = <function MetadataMapping.__not_implemented at 0x7f0c18356560>, custom_decoding_func: 'Callable[[bytes], Any]' = <function MetadataMapping.__not_implemented at 0x7f0c18356560>)MetadataMapping(column_family: 'str', column_name: 'str', metadata_key: 'str', encoding: 'Encoding', custom_encoding_func: 'Callable[[Any], bytes]' = <function MetadataMapping.__not_implemented at 0x7f0c18356560>, custom_decoding_func: 'Callable[[bytes], Any]' = <function MetadataMapping.__not_implemented at 0x7f0c18356560>)