def get_parm_val(parm=None,key=None):
  """ 
  Return the value of a key 
  
  >>> get_parm_val(parm={'test':'val'},key='test')
  'val'
  >>> get_parm_val(parm={'test':'val'},key='foo')
  >>>  
  """
  if parm and key in parm.keys():
    return parm[key]
  else:
    return None