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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def InitUser():
 """Initialize application user. Retrieve existing user credentials from datastore or add new user. Returns: AppUser instance of the application user. """

  result = AppUser.query(AppUser.user == users.get_current_user()).fetch()

  if result:
    app_user = result[0]
  else:
    app_user = AppUser(user=users.get_current_user(),
                       email=users.get_current_user().email())
    app_user.put()

  return app_user