def get_nearby_stops(geo_stops, linestring, side, buffer=cs.BUFFER):
    """
    Given a GeoDataFrame of stops, a Shapely LineString in the
    same coordinate system, a side of the LineString
    (string; 'left' = left hand side of LineString,
    'right' = right hand side of LineString, or
    'both' = both sides), and a buffer in the distance units of that
    coordinate system, do the following.
    Return a GeoDataFrame of all the stops that lie within
    ``buffer`` distance units to the ``side`` of the LineString.
    """
    b = buffer_side(linestring, side, buffer)

    # Collect stops
    return geo_stops.loc[geo_stops.intersects(b)].copy()