def ecdsa_private_key(privkey_str=None, compressed=None):
    """
    Make a private key, but enforce the following rule:
    * unless the key's hex encoding specifically ends in '01', treat it as uncompressed.
    """
    if compressed is None:
        compressed = False
        if privkey_str is not None:
            if len(privkey_str) == 66 and privkey_str[-2:] == '01':
                compressed = True

    return _ECPrivateKey(privkey_str, compressed=compressed)