(self, i_j)
return self._grid[i, j]
Returns the object placed in the row ``i`` and column ``j``.
        The indices are 0-based.

        Examples
        ========

        >>> from sympy.categories import Object, NamedMorphism
        >>> from sympy.categories import Diagram, DiagramGrid
        >>> A = Object("A")
        >>> B = Object("B")
        >>> C = Object("C")
        >>> f = NamedMorphism(A, B, "f")
        >>> g = NamedMorphism(B, C, "g")
        >>> diagram = Diagram([f, g])
        >>> grid = DiagramGrid(diagram)
        >>> (grid[0, 0], grid[0, 1])
        (Object("A"), Object("B"))
        >>> (grid[1, 0], grid[1, 1])
        (None, Object("C"))
Returns the object placed in the row ``i`` and column ``j``.
        The indices are 0-based.
Returns the object placed in the row i and column j . The indices are 0 - based .
def __getitem__(self, i_j):
        """
        Returns the object placed in the row ``i`` and column ``j``.
        The indices are 0-based.

        Examples
        ========

        >>> from sympy.categories import Object, NamedMorphism
        >>> from sympy.categories import Diagram, DiagramGrid
        >>> A = Object("A")
        >>> B = Object("B")
        >>> C = Object("C")
        >>> f = NamedMorphism(A, B, "f")
        >>> g = NamedMorphism(B, C, "g")
        >>> diagram = Diagram([f, g])
        >>> grid = DiagramGrid(diagram)
        >>> (grid[0, 0], grid[0, 1])
        (Object("A"), Object("B"))
        >>> (grid[1, 0], grid[1, 1])
        (None, Object("C"))

        """
        i, j = i_j
        return self._grid[i, j]
def __getitem__ ( self , i_j ) : i , j = i_j return self . _grid [ i , j ]