code: def exp(self):
      r"""Approximates the exponential function using a limit approximation:
  
      .. math::
  
          exp(x) = \lim_{n \\rightarrow \\infty} (1 + x / n) ^ n
  
      Here we compute exp by choosing n = 2 ** d for some large d equal to
      `iterations`. We then compute (1 + x / n) once and square `d` times.
  
      Set the number of iterations for the limit approximation with
      config.exp_iterations.
      """  # noqa: W605
      itecs = cfg.safety.mpc.functions.exp_iterations
  
      result = 1 + self.div(2**iters)
      for _ in range(iters):
          result = result.square()
      return result
  
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 1 for calling a global function with example usage: exp() and returns: result