<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _build_return_code_enum():
 """ Creates an IntEnum containing all the XTT return codes. Finds all return codes by scanning the FFI for items whose names match the pattern "XTT_RETURN_<X>". The name of the result enum value is the suffix "<X>". """

    prefix = 'XTT_RETURN_'
    codes = {k[len(prefix):]:v for (k, v) in vars(_lib).items() if k.startswith(prefix)}
    return IntEnum('ReturnCode', codes)