an error in sending json data to flask server [duplicate]

@app.route('/predict', methods=['POST'])
def predict():
    if request.method == 'POST':
        data_raw = request.get_json()
        print(type(data_raw))  # prints 'dict' in the terminal used to start the server
        data = np.array(data_raw.values()).reshape(1, -1)
        # do model stuff