Sort the table according to the value of attribute attrname.

        Return:
            New class:`PseudoTable` object

def sorted(self, attrname, reverse=False):
        """
        Sort the table according to the value of attribute attrname.

        Return:
            New class:`PseudoTable` object
        """
        attrs = []
        for i, pseudo in self:
            try:
                a = getattr(pseudo, attrname)
            except AttributeError:
                a = np.inf
            attrs.append((i, a))

        # Sort attrs, and build new table with sorted pseudos.
        return self.__class__([self[a[0]] for a in sorted(attrs, key=lambda t: t[1], reverse=reverse)])