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_blocks = self.blocks*other.blocks
+            # Convert Zero objects to ZeroMatrix with proper dimensions
+            from sympy.core.numbers import Zero
+            def fix_zero_blocks(blocks, self_rowblocksizes, other_colblocksizes):
+                fixed_blocks = []
+                for i in range(blocks.shape[0]):
+                    row = []
+                    for j in range(blocks.shape[1]):
+                        block = blocks[i, j]
+                        if isinstance(block, Zero):
+                            # Zero block should have dimensions from row i of self and col j of other
+                            rows = self_rowblocksizes[i]
+                            cols = other_colblocksizes[j]
+                            block = ZeroMatrix(rows, cols)
+                        row.append(block)
+                    fixed_blocks.append(row)
+                return fixed_blocks
+            fixed_blocks = fix_zero_blocks(result_blocks, self.rowblocksizes, other.colblocksizes)
+            return BlockMatrix(fixed_blocks)
         return self * other

xas