code: def penn2morphy(penntag, returnNone=False, default_to_noun=False) -> str:
      
      morphy_tag = {'NN':'n', 'JJ':'a', 'VB':'v', 'RB':'r'}
      try:
          return morphy_tag[penntag[:2]]
      except:
          if returnNone:
              return None
          elif default_to_noun:
              return 'n'
          else:
              return ''
docs: Converts tags from Penn format (input: single string) to Morphy.