docs: def load_keypair(keypair_file):
      '''load a keypair from a keypair file. We add attributes key (the raw key)
         and public_key (the url prepared public key) to the client.
  
         Parameters
         ==========
         keypair_file: the pem file to load.
      '''
      from Crypto.PublicKey import RSA
  
      # Load key
      with open(keypair_file, 'rb') as filey:
          key = RSA.import_key(filey.read())
  
      return quote_plus(key.publickey().exportKey().decode('utf-8'))