def does_sqlatype_require_index_len(
        coltype: Union[TypeEngine, VisitableType]) -> bool:
    """
    Is the SQLAlchemy column type one that requires its indexes to have a
    length specified?

    (MySQL, at least, requires index length to be specified for ``BLOB`` and
    ``TEXT`` columns:
    http://dev.mysql.com/doc/refman/5.7/en/create-index.html.)
    """
    coltype = _coltype_to_typeengine(coltype)
    if isinstance(coltype, sqltypes.Text):
        return True
    if isinstance(coltype, sqltypes.LargeBinary):
        return True
    return False