input: Write a function to generate a voltage signal with random noise using a Python script. The signal should have a frequency of 250 Hz and an amplitude of 1 V. The function should return the generated voltage signal.
  
  import numpy as np
  
  def generate_noisy_signal():
      freq = 250
      amplitude = 1
      t = np.linspace(0, 1, 1000)
      voltage_signal = np.sin(2*np.pi*freq*t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal
  
  assert len(generate_noisy_signal()) == 1000
  assert np.allclose(np.mean(generate_noisy_signal()), 0, atol=0.1)
  assert np.allclose(np.std(generate_noisy_signal()), 0.1, atol=0.05)
output: def generate_noisy_signal():
      freq = 250
      amplitude = 1
      t = np.linspace(0, 1, 1000)
      voltage_signal = np.sin(2*np.pi*freq*t) + np.random.normal(0, 0.1, 1000)
      return voltage_signal