def verify(info):
    types_key = {} # maps key to types
    required_keys = set()
    for key, required, types, unused_descr in KEYS:
        types_key[key] = types
        if required:
            required_keys.add(key)

    for key in info:
        if key not in types_key:
            sys.exit("Error: unknown key '%s' in construct.yaml" % key)
        elt = info[key]
        types = types_key[key]
        if not isinstance(elt, types):
            sys.exit("Error: key '%s' points to %s,\n"
                     "       expected %s" % (key, type(elt), types))

    for key in required_keys:
        if info not in key:
            sys.exit("Error: Required key '%s' not found in construct.yaml" %
                     key)
dataset/ETHPy150Open conda/constructor/constructor/construct.py/verify/swapped operands of `not in`