Returns the numeric columns of the Manager.

        Returns:
            List of index names.

def numeric_columns(self, include_bool=True):
        """Returns the numeric columns of the Manager.

        Returns:
            List of index names.
        """
        columns = []
        for col, dtype in zip(self.columns, self.dtypes):
            if is_numeric_dtype(dtype) and (
                include_bool or (not include_bool and dtype != np.bool_)
            ):
                columns.append(col)
        return columns