code: def _chebyshev_polynomials(self, terms):
      r"""Evaluates odd degree Chebyshev polynomials at x
  
      Chebyshev Polynomials of the first kind are defined as
  
      .. math::
          P_0(x) = 1, P_1(x) = x, P_n(x) = 2 P_{n - 1}(x) - P_{n-2}(x)
  
      Args:
          self (MPCTensor): input at which polynomials are evaluated
          terms (int): highest degree of Chebyshev polynomials.
                          Must be even and at least 6.
      Returns:
          MPCTensor of polynomials evaluated at self of shape `(terms, *self)`
      """
      if terms % 2 != 0 or terms < 6:
          raise ValueError("Chebyshev terms must be even and >= 6")
  
      polynomials = [self.clone()]
      y = 4 * self.square() - 2
      z = y - 1
      polynomials.append(z.mul(self))
  
      for k in range(2, terms // 2):
          next_polynomial = y * polynomials[k - 1] - polynomials[k - 2]
          polynomials.append(next_polynomial)
  
      return mpc.stack(polynomials)
  
imports: import math
  import torch
  from fate.arch.protocol import mpc
  from ..common.util import chebyshev_series
  from ..config import cfg
label_desc: Use image node_id 12 for calling a global function with example usage: _chebyshev_polynomials(terms) and returns: mpc