code: def in_casapy(helper, vis=None):
      
      import numpy as np, sys
      from correct_ant_posns import correct_ant_posns
  
      info = correct_ant_posns(vis, False)
      if len(info) != 3 or info[0] != 0 or not len(info[1]):
          helper.die('failed to fetch VLA antenna positions; got %r', info)
  
      antenna = info[1]
      parameter = info[2]
  
      with open(helper.temppath('info.npy'), 'wb') as f:
          np.save(f, antenna)
          np.save(f, parameter)
docs: This function is run inside the weirdo casapy IPython environment! A
      strange set of modules is available, and the
      `pwkit.environments.casa.scripting` system sets up a very particular
      environment to allow encapsulated scripting.