def _txt2obj(backend, name):
    """
    Converts a Python string with an ASN.1 object ID in dotted form to a
    ASN1_OBJECT.
    """
    name = name.encode('ascii')
    obj = backend._lib.OBJ_txt2obj(name, 1)
    backend.openssl_assert(obj != backend._ffi.NULL)
    return obj
