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)
+            result = self.blocks*other.blocks
+            # Convert any Zero objects to ZeroMatrix with correct dimensions
+            from sympy.core.numbers import Zero
+            if hasattr(result, 'applyfunc'):
+                # Create a new matrix with proper ZeroMatrix objects
+                new_rows = result.rows
+                new_cols = result.cols
+                from sympy import Matrix
+                new_result = Matrix(new_rows, new_cols, lambda i, j:
+                    ZeroMatrix(self.rowblocksizes[i], other.colblocksizes[j])
+                    if isinstance(result[i, j], Zero) and not hasattr(result[i, j], 'cols')
+                    else result[i, j])
+                return BlockMatrix(new_result)
         return self * other

yahoo