def getModel(pointFeature):
    args = pointFeature.toDictionary()
    lon = args.get('longitude')
    lat = args.get('latitude')
    point = ee.Geometry.Point([lon, lat])
    # Create image collection
    l8_collection = ee.ImageCollection(
        'LANDSAT/LC08/C01/T1_SR').filterBounds(point).filterDate('2015-01-01', '2018-01-01')
    info = l8_collection.getRegion(point, 30).getInfo()
    header = info[0]
    data = np.array(info[1:])
    results = analysis_function(header, data)
    return ee.Feature(None, results)

Results = points.map(getModel)

ee.ee_exception.EEException: Failed to decode JSON.
Error: Field 'value' of object '{"type":"ArgumentRef","value":null}' is missing or null.
Object: {"type":"ArgumentRef","value":null}.