Traceback (most recent call last):
  File "new_rom_tb.py", line 29, in <module>
    run_simulation(dut, main_generator(dut), clocks, vcd_name="sim.vcd")
  File "/home/ishan/gsoc/environment/HDMI2USB-litex-firmware/third_party/litex/litex/gen/sim/core.py", line 385, in run_simulation
    with Simulator(*args, **kwargs) as s:
  File "/home/ishan/gsoc/environment/HDMI2USB-litex-firmware/third_party/litex/litex/gen/sim/core.py", line 244, in __init__
    self.fragment = fragment_or_module.get_fragment()
  File "/home/ishan/gsoc/environment/HDMI2USB-litex-firmware/third_party/litex/litex/gen/fhdl/module.py", line 102, in get_fragment
    self.finalize()
  File "/home/ishan/gsoc/environment/HDMI2USB-litex-firmware/third_party/litex/litex/gen/fhdl/module.py", line 156, in finalize
    subfragments = self._collect_submodules()
  File "/home/ishan/gsoc/environment/HDMI2USB-litex-firmware/third_party/litex/litex/gen/fhdl/module.py", line 148, in _collect_submodules
    if not submodule.get_fragment_called:
AttributeError: 'NoneType' object has no attribute 'get_fragment_called'