code: def _zseries_to_cseries(zs):
      """Covert z-series to a Chebyshev series.
  
      Covert a z series to the equivalent Chebyshev series. The result is
      never an empty array. The dtype of the return is the same as that of
      the input. No checks are run on the arguments as this routine is for
      internal use.
  
      Parameters
      ----------
      zs : 1-D ndarray
          Odd length symmetric z-series, ordered from  low to high.
  
      Returns
      -------
      c : 1-D ndarray
          Chebyshev coefficients, ordered from  low to high.
  
      """
      n = (zs.size + 1) // 2
      c = zs[n - 1 :].copy()
      c[1:n] *= 2
      return c
  
imports: from __future__ import division, absolute_import, print_function
  import warnings
  import numpy
  import numpy.linalg
  from numpy.core.multiarray import normalize_axis_index
  from .None import polyutils
  from ._polybase import ABCPolyBase
label_desc: Use image node_id 2 for calling a global function with example usage: _zseries_to_cseries(zs) and returns: c