def access(db,key,field):
    '''Return the filler of the field in db[key],
       if there is one; otherwise, return None'''
    if field in db[key]:
        return db[key][field]
    else:
        return None

def accessWithPrint(db,key,field):
    '''Return the filler of the field in db[key],
       if there is one; otherwise, return None'''
    print("")
    print("==>Just called accessWithPrint") 
    print("key=",key,"field=",field)
    print("db[key] on the next line:")
    print("  ",db[key])
    if field in db[key]:
        print("db[key][field]=",db[key][field])
        return db[key][field]
    else:
        return None

def pp(first,last,books):
    print(first,last,end="")
    if books:
      print(" is the author of the following books:")
      for b in books:
         print(b)
    else:
      print(" is not an author")

def main():
  db = {
    'jgoodall'  : {'surname'  : 'Goodall',\
                   'forename' : 'Jane',\
                   'born'     : 1934,\
                   'died'     : None,\
                   'notes'    : 'primate researcher',\
                   'author'   : ['In the Shadow of Man', 'The Chimpanzees of Gombe']},\
    'rfranklin' : {'surname'  : 'Franklin',\
                   'forename' : 'Rosalind',\
                   'born'     : 1920,\
                   'died'     : 1957,\
                   'notes'    : 'contributed to discovery of DNA'},\
     'rcarson'  : {'surname'  : 'Carson',\
                   'forename' : 'Rachel',\
                   'born'     : 1907,\
                   'died'     : 1964,\
                   'notes'    : 'raised awareness of effects of DDT',\
                   'author'   : ['Silent Spring']}}

  print("====Printing all the authors:")
  for k in db:
    if 'author' in db[k]:
       pp(db[k]['forename'],db[k]['surname'],db[k]['author'])
    else:
       pp(db[k]['forename'],db[k]['surname'],[])
  print("=========")     

  print('jgoodall was born in',access(db,'jgoodall','born'))
  print('jgoodall was born in',accessWithPrint(db,'jgoodall','born'))
  print('jgoodall wrote these books',accessWithPrint(db,'jgoodall','author'))
  print('rfranklin wrote these books',accessWithPrint(db,'rfranklin','author'))

main()