code: def set_secret_key(token):
      
      if not isinstance(token, string_types):
          raise exceptions.ConfigurationError('Expected string value for token.')
  
      config.secret_key = token
docs: Initializes a Authentication and sets it as the new default global authentication.
      It also performs some checks before saving the authentication.
  
      :Example
  
      >>> # Expected format for secret key:
      >>> import payplug
      >>> payplug.set_secret_key('sk_test_somerandomcharacters')
  
      :param token: your secret token (live or sandbox)
      :type token: string