@lru_cache(maxsize=<NUM_LIT:8>)<EOL>def _get_scheme_map(input_encoding, output_encoding):
return SchemeMap(SCHEMES[input_encoding], SCHEMES[output_encoding])<EOL>
Provides a caching layer on top of `SchemeMap` objects to allow faster
    access to scheme maps we've instantiated once.

    :param input_encoding: Input encoding. Must be defined in `SCHEMES`.
    :param output_encoding: Input encoding. Must be defined in `SCHEMES`.