input: Write a function to generate a voltage signal with random noise at a specified frequency and amplitude. The function should return the voltage signal as a numpy array.
  
  def generate_voltage_signal(frequency, amplitude):
      t = np.linspace(0, 1, 1000)
      voltage_signal = np.sin(2 * np.pi * frequency * t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal
  
  assert np.allclose(generate_voltage_signal(250, 1), [some_expected_value], atol=0.01, rtol=0.01)
output: def generate_voltage_signal(frequency, amplitude):
      t = np.linspace(0, 1, 1000)
      voltage_signal = amplitude * np.sin(2 * np.pi * frequency * t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal