Combine query endpoint and params.

    Example::

        >>> add_params("https://www.google.com/search", {"q": "iphone"})
        https://www.google.com/search?q=iphone

def add_params(endpoint, params):
    """
    Combine query endpoint and params.

    Example::

        >>> add_params("https://www.google.com/search", {"q": "iphone"})
        https://www.google.com/search?q=iphone
    """
    p = PreparedRequest()
    p.prepare(url=endpoint, params=params)
    if PY2:  # pragma: no cover
        return unicode(p.url)
    else:  # pragma: no cover
        return p.url