try to parse a ndarray like into a date column
            try to coerce object in epoch/iso formats and
            integer/float in epcoh formats, return a boolean if parsing
            was successful

def _try_convert_to_date(self, data):
        """ try to parse a ndarray like into a date column
            try to coerce object in epoch/iso formats and
            integer/float in epcoh formats, return a boolean if parsing
            was successful """

        # no conversion on empty
        if not len(data):
            return data, False

        new_data = data
        if new_data.dtype == 'object':
            try:
                new_data = data.astype('int64')
            except:
                pass

        # ignore numbers that are out of range
        if issubclass(new_data.dtype.type, np.number):
            in_range = (isnull(new_data.values) | (new_data > self.min_stamp) |
                        (new_data.values == iNaT))
            if not in_range.all():
                return data, False

        date_units = (self.date_unit,) if self.date_unit else self._STAMP_UNITS
        for date_unit in date_units:
            try:
                new_data = to_datetime(new_data, errors='raise',
                                       unit=date_unit)
            except ValueError:
                continue
            except:
                break
            return new_data, True
        return data, False