def add_formatter(self, col, handler):

        if isinstance(col, str):
            if col in self.headers:
                col = self.headers.index(col) # get 'key' index from each data
            else:
                raise KeyError

        if not col > self.width:
            self._formatters.append((col, handler))
        else:
            raise InvalidDatasetIndex

        return True
Adds a :ref:`formatter` to the :class:`Dataset`.
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/tablib-0.10.0/tablib/core.py/Dataset.add_formatter