def codeChecker(code, wetland_type):
    match_dict = {'ay': ['LOBA', 'LOFP'],
                  'bg': ['LEBA', 'LEFP', 'LEFR', 'TEBA', 'TEFL', 'TEFR', 'TESL']}
    if wetland_type not in match_dict[code]:
        return code
    else:
        return 'No error'

codeChecker('ay', 'LOBA') # wetland type in allowable values
# returns 'No error'
codeChecker('ay', 'TEBA') # wetland type outside of allowable values
# returns 'ay'