'Add an AWS API-compatible parameter list to a dictionary.
:type params: dict
:param params: The parameter dictionary
:type items: list
:param items: Items to be included in the list
:type label: string
:param label: The parameter list\'s name'

def _build_list_params(self, params, items, label):

    if isinstance(items, six.string_types):
        items = [items]
    for i in range(1, (len(items) + 1)):
        params[('%s.%d' % (label, i))] = items[(i - 1)]
