def neighbors(lines, of):
    """Find the indices in a list of LineStrings that touch a given LineString.
    
    Args:
        lines: list of LineStrings in which to search for neighbors
        of: the LineString which must be touched
        
    Returns:
        list of indices, so that all lines[indices] touch the LineString of
    """
    return [k for k, line in enumerate(lines) if line.touches(of)]