Generate a new random security token.

     >>> len(generate_token()) == 50
     True

     Returns:
       string

def generate_token():
    """ Generate a new random security token.

     >>> len(generate_token()) == 50
     True

     Returns:
       string
    """
    length = 50
    stringset = string.ascii_letters + string.digits
    token = ''.join([stringset[i % len(stringset)] for i in [ord(x) for x in os.urandom(length)]])
    return token