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)
+            # Compute the raw result
+            raw_result = self.blocks*other.blocks
+            # Post-process to replace Zero objects with ZeroMatrix objects
+            from sympy.matrices.immutable import ImmutableDenseMatrix
+            result_blocks = []
+            for i in range(raw_result.shape[0]):
+                row = []
+                for j in range(raw_result.shape[1]):
+                    element = raw_result[i, j]
+                    # Check if the element is a Zero object (from sympy.core.numbers)
+                    if hasattr(element, 'is_zero') and element.is_zero and not hasattr(element, 'cols'):
+                        # Replace with ZeroMatrix of appropriate dimensions
+                        row_dim = self.rowblocksizes[i]
+                        col_dim = other.colblocksizes[j]
+                        element = ZeroMatrix(row_dim, col_dim)
+                    row.append(element)
+                result_blocks.append(row)
+            return BlockMatrix(ImmutableDenseMatrix(result_blocks))
         return self * other

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