def inject_metadata_descriptions(self, term_dict):
        '''
        Inserts a set of descriptions of meta data terms.  These will be displayed
        below the scatter plot when a meta data term is clicked. All keys in the term dict
        must occur as meta data.

        Parameters
        ----------
        term_dict: dict {metadataname: str: 'explanation to insert', ...}

        Returns
        -------
        self: ScatterChart
        '''
        assert type(term_dict) == dict
        if not self.term_doc_matrix.metadata_in_use():
            raise TermDocMatrixHasNoMetadataException("No metadata is present in the term document matrix")
        # This doesn't seem necessary. If a definition's not in the corpus, it just won't be shown.
        # if set(term_dict.keys()) - set(self.term_doc_matrix.get_metadata()) != set():
        #    raise Exception('The following meta data terms are not present: '
        #                    + ', '.join(list(set(term_dict.keys()) - set(self.term_doc_matrix.get_metadata()))))

        if sys.version_info[0] == 2:
            assert set([type(v) for v in term_dict.values()]) - set([str, unicode]) == set()
        else:
            assert set([type(v) for v in term_dict.values()]) - set([str]) == set()

        self.metadata_descriptions = term_dict
        return self

        Inserts a set of descriptions of meta data terms.  These will be displayed
        below the scatter plot when a meta data term is clicked. All keys in the term dict
        must occur as meta data.

        Parameters
        ----------
        term_dict: dict {metadataname: str: 'explanation to insert', ...}

        Returns
        -------
        self: ScatterChart
        
scattertext/ScatterChart.py