code: def ar1(rho, mu, sigma, size=1):
      
      return np.array([x for x in ar1_gen(rho, mu, sigma, size)])
docs: Return an autoregressive series of order one AR(1).
  
      .. math::
          X_t = \mu_t + \rho (X_{t-1}-\mu_{t-1} + \epsilon_t
  
      If mu is a sequence and size > len(mu), the algorithm loops through
      mu.
  
      :Stochastics:
          rho : scalar in [0,1]
          mu : scalar or sequence
          sigma : scalar > 0
          size : integer