code: def rc2poly(kr, r0=None):
      
      # Initialize the recursion
      from .levinson import levup
      p = len(kr)              #% p is the order of the prediction polynomial.
      a = numpy.array([1, kr[0]])           #% a is a true polynomial.
      e = numpy.zeros(len(kr))
  
      if r0 is None:
          e0 = 0
      else:
          e0 = r0
  
      e[0] = e0 * (1. - numpy.conj(numpy.conjugate(kr[0])*kr[0]))
  
      # Continue the recursion for k=2,3,...,p, where p is the order of the
      # prediction polynomial.
  
      for k in range(1, p):
          [a, e[k]] = levup(a, kr[k], e[k-1])
  
      efinal = e[-1]
      return a, efinal
docs: convert reflection coefficients to prediction filter polynomial
  
      :param k: reflection coefficients