def buffer_bbox(bbox_osm):
    """
    Buffers a EPSG:4326 bounding box slightly to ensure covering the whole area of interest.
    :param bbox_osm: array-like of four coordinates: miny, minx, maxy, maxx.
    :return: array-like of four coordinates: miny, minx, maxy, maxx
    """
    offset_lat, offset_lon = 0.02, 0.02  # degrees
    bbox_osm[0] -= offset_lat  # min lat
    bbox_osm[1] -= offset_lon  # min lon
    bbox_osm[2] += offset_lat  # max lat
    bbox_osm[3] += offset_lon  # max lon
    return bbox_osm