How to use the databases.open_database function in databases

def _post_init(self):
        for o in self.savedession:
            filename = self.savedession[o]
            databases.open_database(filename)

        try:
            wx.GetApp().nb_left.select_page(0)
        except IndexError:
            pass

        # Bind *after* opening the databases in the session, because the
        # session must be refreshed only when databases are opened manually
        databases.open_database_event.bind(self._handle_open_database)
        databases.close_database_event.bind(self._handle_close_database)

def open_database(self, event, filename=None):
        if core_api.block_databases():
            databases.open_database(filename)
            core_api.release_databases()

def new_database(self, event, filename=None):
        if core_api.block_databases():
            fn = databases.create_database(filename=filename)

            if fn:
                databases.open_database(fn)

            core_api.release_databases()

# the dialogs to save the database
        self.propmanager.close(self.filename)

        if databases.close_database(self.filename):
            shutil.copy2(self.filename, self.backup.GetPath())

            if self.value == 0:
                dbdeps.Database(self.filename).add((self.ext, ))
            elif self.value == 1:
                dbdeps.Database(self.filename).remove((self.ext, ))
            else:
                dbdeps.Database(self.filename).remove((self.ext, ),
                                                                ignored=True)

            # Use CallAfter or segfaults may happen
            wx.CallAfter(databases.open_database, self.filename,
                                                        open_properties=True)
            # Note that no other operation should be done on the database
            #  directly here, because opening the database may fail e.g.
            #  because of the compatibility checks
        else:
            self.propmanager.open(self.filename)

        # Always close the dialog because the property settings have been
        # reset by closing and reopening the property tab
        self._close()

def _skip(self, event):
        self._close()
        # Use CallAfter or segfaults may happen e.g. if re-opening after
        # changing the dependencies in the properties tab
        wx.CallAfter(databases.open_database, self.updater.get_filename(),
                                        check_new_extensions=False,
                                        open_properties=self.open_properties)

def _add(self, event):
        filename = self.updater.get_filename()
        shutil.copy2(filename, self.backup.GetPath())
        dbdeps.Database(filename).add(self.deplist)
        self._close()

        # Use CallAfter or segfaults may happen e.g. if re-opening after
        # changing the dependencies in the properties tab
        wx.CallAfter(databases.open_database, filename,
                                        open_properties=self.open_properties)