old_contents: """
  Ricker wavelet generator for seismic simulation
  ===============================================
  
  """
  
  from __future__ import division, print_function, absolute_import
new_contents: """
  Ricker wavelet generator for seismic simulation
  ===============================================
  
  """
  
  from __future__ import division, print_function, absolute_import
  
  from .ricker import ricker
  
subject: Make ricker funciton available in the top level.