input: Write a function to generate a voltage signal with random noise based on a given signal frequency and amplitude. The returned signal should be a NumPy array representing the voltage values at different time points. The time points should cover one second with 1000 samples.
  
  def generate_voltage_signal(freq, amplitude):
      t = np.linspace(0, 1, 1000)
      voltage_signal = amplitude * np.sin(2 * np.pi * freq * t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal
  
  assert np.allclose(generate_voltage_signal(250, 1), [amplitude * np.sin(2 * np.pi * 250 * t) for t in np.linspace(0, 1, 1000)] + np.random.normal(0, 0.1, 1000))
output: def generate_voltage_signal(freq, amplitude):
      t = np.linspace(0, 1, 1000)
      voltage_signal = amplitude * np.sin(2 * np.pi * freq * t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal