Get the index of the requested dimension.

        Args:
            dimension: Dimension to look up by name or by index

        Returns:
            Integer index of the requested dimension

def get_dimension_index(self, dimension):
        """Get the index of the requested dimension.

        Args:
            dimension: Dimension to look up by name or by index

        Returns:
            Integer index of the requested dimension
        """
        if isinstance(dimension, int):
            if (dimension < (self.ndims + len(self.vdims)) or
                dimension < len(self.dimensions())):
                return dimension
            else:
                return IndexError('Dimension index out of bounds')
        dim = dimension_name(dimension)
        try:
            dimensions = self.kdims+self.vdims
            return [i for i, d in enumerate(dimensions) if d == dim][0]
        except IndexError:
            raise Exception("Dimension %s not found in %s." %
                            (dim, self.__class__.__name__))