Finished

Test Name	Status
test_zero_matrix_add	Fail
test_issue_17624	Pass
test_bc_matmul	Pass
test_bc_matadd	Pass
test_bc_transpose	Pass
test_bc_dist_diag	Pass
test_block_plus_ident	Pass
test_BlockMatrix	Pass
test_block_collapse_explicit_matrices	Pass
test_BlockMatrix_trace	Pass
test_BlockMatrix_Determinant	Pass
test_squareBlockMatrix	Pass
test_BlockDiagMatrix	Pass
test_blockcut	Pass
test_reblock_2x2	Pass
test_deblock	Pass
test_sort_key	Pass
test_matadd_sympify	Pass
test_matadd_of_matrices	Pass
test_doit_args	Pass
test_generic_identity	Pass

     def _blockmul(self, other):
         if (isinstance(other, BlockMatrix) and
                 self.colblocksizes == other.rowblocksizes):
+            return BlockMatrix(self.blocks*other.blocks)
+            from sympy.core.numbers import Zero
+            # Perform block multiplication
+            result_blocks = self.blocks*other.blocks
+            # Convert Zero objects back to ZeroMatrix with appropriate dimensions
+            def convert_zero_to_zeromatrix(block, i, j):
+                if isinstance(block, Zero):
+                    # Get dimensions from the corresponding blocks
+                    rows = self.rowblocksizes[i]
+                    cols = other.colblocksizes[j]
+                    return ZeroMatrix(rows, cols)
+                return block
+            # Apply conversion to each block
+            converted_data = [[convert_zero_to_zeromatrix(result_blocks[i, j], i, j)
+                              for j in range(result_blocks.cols)]
+                             for i in range(result_blocks.rows)]
+            return BlockMatrix(converted_data)
         return self * other

let it go