input: Write a Python function to generate a voltage signal with random noise of a given frequency and amplitude. The function should take two parameters: frequency (in Hz) and amplitude (in V). The signal should be generated over one second with 1000 samples. 
  
  def generate_signal(frequency, amplitude):
      import numpy as np 
      
      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.isclose(generate_signal(250, 1)[0], np.sin(2 * np.pi * 250 * 0 / 1000) + np.random.normal(0, 0.1, 1))
  assert np.isclose(generate_signal(500, 2)[0], np.sin(2 * np.pi * 500 * 0 / 1000) + np.random.normal(0, 0.1, 1))
  assert np.isclose(generate_signal(100, 0.5)[0], np.sin(2 * np.pi * 100 * 0 / 1000) + np.random.normal(0, 0.1, 1))
  assert np.isclose(generate_signal(1000, 3)[0], np.sin(2 * np.pi * 1000 * 0 / 1000) + np.random.normal(0, 0.1, 1))
  assert len(generate_signal(250, 1)) == 1000
output: def generate_signal(frequency, amplitude):
      import numpy as np 
      
      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