code: import numpy as np
  import math, random
  
  # Generate a noisy multi-sin wave 
  def sine_2(X, signal_freq=60.):
      return (np.sin(2 * np.pi * (X) / signal_freq) + np.sin(4 * np.pi * (X) / signal_freq)) / 2.0
  
  def noisy(Y, noise_range=(-0.05, 0.05)):
      noise = np.random.uniform(noise_range[0], noise_range[1], size=Y.shape)
      return Y + noise
  
  def sample(sample_size):
      random_offset = random.randint(0, sample_size)
      X = np.arange(sample_size)
      Y = noisy(sine_2(X + random_offset))
      return Y
apis: numpy.random.uniform numpy.sin numpy.arange