code: def arma2ma(ar, ma, lags=100):
      """
      A finite-lag approximate MA representation of an ARMA process.
  
      Parameters
      ----------
      ar : ndarray
          The auto regressive lag polynomial.
      ma : ndarray
          The moving average lag polynomial.
      lags : int
          The number of coefficients to calculate.
  
      Returns
      -------
      ndarray
          The coefficients of AR lag polynomial with nobs elements.
  
      Notes
      -----
      Equivalent to ``arma_impulse_response(ma, ar, leads=100)``
      """
      return arma_impulse_response(ar, ma, leads=lags)
  
imports: from statsmodels.compat.numpy import NP_LT_2
  from statsmodels.compat.pandas import Appender
  import warnings
  import numpy
  from scipy import linalg, optimize, signal
  from statsmodels.tools.docstring import Docstring, remove_parameters
  from statsmodels.tools.validation import array_like
label_desc: Use image node_id 7 for calling a global function with example usage: arma2ma(ar, ma, lags) and returns: arma_impulse_response