def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def insert_accented(self, c, accent):
        if c.isalpha():
            if c.isupper():
                cap = 'capital'
            else:
                cap = 'small'
            try:
                c = lookup("latin %s letter %c with %s" % (cap, c, accent))
                self.insert(INSERT, c)
                # Prevent plain letter from being inserted too, tell Tk to
                # stop handling this event
                return "break"
            except KeyError, e:
                pass