code: def _mesh(mesher, n_processes=None):
      """Helper function to make a mesh"""
      xlim = mesher.limits[0]
      ylim = mesher.limits[1]
      x = np.arange(xlim[0], xlim[1], mesher.delta)
      y = np.arange(ylim[0], ylim[1], mesher.delta)
      xx, yy = np.meshgrid(x, y)
      xypairs = np.vstack([xx.reshape(-1), yy.reshape(-1)]).T
  
      # Get z-value
  
      # Setup Pool of processes for parallel evaluation
      pool = None if n_processes is None else mp.Pool(n_processes)
  
      if pool is None:
          z = mesher.func(xypairs)
      else:
          results = pool.map(
              mesher.func, np.array_split(xypairs, pool._processes)
          )
          z = np.concatenate(results)
  
      # Close Pool of Processes
      if n_processes is not None:
          pool.close()
  
      zz = z.reshape(xx.shape)
      return (xx, yy, zz)
  
file_path: pyswarms/pyswarms/utils/plotters/plotters.py
imports: import logging
  import matplotlib.pyplot
  import numpy
  import multiprocessing
  from matplotlib import animation, cm
  from mpl_toolkits.mplot3d import Axes3D
  from ..reporter import Reporter
  from .formatters import Animator, Designer
label_desc: Use image node_id 5 for calling a global function with example usage: _mesh(mesher, n_processes) and returns: xx,  yy,  zz