URL encodes the parameters.

    :param params: The parameters
    :type params: list of key/value tuples.

    :rtype: string

def urlencode_params(params):
    """URL encodes the parameters.

    :param params: The parameters
    :type params: list of key/value tuples.

    :rtype: string
    """
    # urlencode does not handle unicode strings in Python 2.
    # Firstly, normalize the values so they get encoded correctly.
    params = [(key, normalize_for_urlencode(val)) for key, val in params]
    # Secondly, unquote unreserved chars which are incorrectly quoted
    # by urllib.urlencode, causing invalid auth signatures. See GH #72
    # for more info.
    return requests.utils.unquote_unreserved(urlencode(params))