def tcp(*args):
    """Create a tcp connection string.

    Function can have a single argument with the full address, or
    2 arguments where first is the address and second is the port.

    :rtype: str.

    """
    if len(args) == 2:
        address = '{}:{}'.format(*args)
    else:
        address = args[0]
    return 'tcp://{}'.format(address)
