# Pastebin YGpTLHUf
File "/home/x/Development/symbiflow-examples/xc7/install/share/symbiflow/scripts/fix_xc7_carry.py", line 558, in fixup_congested_rows
    check_if_rest_of_carry4_is_unused(cellname, cell_idx + 1):
  File "/home/x/Development/symbiflow-examples/xc7/install/share/symbiflow/scripts/fix_xc7_carry.py", line 507, in check_if_rest_of_carry4_is_unused
    assert cell_idx < len(O_ports) - 1