new_contents: 
  import numpy as np
  from taskinit import mstool
  
  
  def extract_ms_data(vis, columns, field="", **kwargs):
      '''
      Extract data points from an MS.
      '''
  
      myms = mstool()
  
      myms.open(vis)
      myms.selectinit(0)
      selection_dict = dict(field=field)
      selection_dict.update(kwargs)
      assert myms.msselect(selection_dict), "Data selection has failed"
  
      if not isinstance(columns, list):
          columns = list(columns)
  
      datadict = myms.getdata(columns)
      myms.close()
  
      for column in columns:
          np.save("{0}_{1}.npy".format(vis.rstrip(".ms"), column.lower()),
                  datadict[column])
  
subject: Save data in an MS into a numpy file