def index(self, item, minindex=0, maxindex=None):
        """Provide an index of first occurence of item in the list. (or raise
        a ValueError if item not present)
        If item is not a string, will raise a TypeError.
        minindex and maxindex are also optional arguments
        s.index(x[, i[, j]]) return smallest k such that s[k] == x and i <= k < j
        """
        if maxindex is None:
            maxindex = len(self)
        minindex = max(0, minindex) - 1
        maxindex = min(len(self), maxindex)
        if not isinstance(item, str):
            raise TypeError(
                'Members of this object must be strings. '
                'You supplied \"%s\"' % type(item))
        index = minindex
        while index < maxindex:
            index += 1
            if item.lower() == self[index].lower():
                return index
        raise ValueError(': list.index(x): x not in list')