code: def rc2is(k):
      
      assert numpy.isrealobj(k), 'Inverse sine parameters not defined for complex reflection coefficients.'
      if max(numpy.abs(k)) >= 1:
          raise ValueError('All reflection coefficients should have magnitude less than unity.')
  
      return (2/numpy.pi)*numpy.arcsin(k)
docs: Convert reflection coefficients to inverse sine parameters.
  
      :param k: reflection coefficients
      :return: inverse sine parameters
  
      .. seealso:: :func:`is2rc`, :func:`rc2poly`, :func:`rc2acC`, :func:`rc2lar`.
  
      Reference: J.R. Deller, J.G. Proakis, J.H.L. Hansen, "Discrete-Time
         Processing of Speech Signals", Prentice Hall, Section 7.4.5.