Convert numpy types to Python types for the Excel writers.

        Parameters
        ----------
        val : object
            Value to be written into cells

        Returns
        -------
        Tuple with the first element being the converted value and the second
            being an optional format

def _value_with_fmt(self, val):
        """Convert numpy types to Python types for the Excel writers.

        Parameters
        ----------
        val : object
            Value to be written into cells

        Returns
        -------
        Tuple with the first element being the converted value and the second
            being an optional format
        """
        fmt = None

        if is_integer(val):
            val = int(val)
        elif is_float(val):
            val = float(val)
        elif is_bool(val):
            val = bool(val)
        elif isinstance(val, datetime):
            fmt = self.datetime_format
        elif isinstance(val, date):
            fmt = self.date_format
        elif isinstance(val, timedelta):
            val = val.total_seconds() / float(86400)
            fmt = '0'
        else:
            val = compat.to_str(val)

        return val, fmt