registered_flow = client.register(
Traceback (most recent call last):
  File "main.py", line 4, in <module>
    pb_flow.register("my project")
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/core/flow.py", line 1603, in register
    registered_flow = client.register(
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/client/client.py", line 734, in register
    serialized_flow = flow.serialize(build=build)  # type: Any
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/core/flow.py", line 1454, in serialize
    storage = self.storage.build()  # type: Optional[Storage]
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/environments/storage/docker.py", line 351, in build
    self._build_image(push=push)
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/environments/storage/docker.py", line 383, in _build_image
    dockerfile_path = self.create_dockerfile_object(directory=tempdir)
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/prefect/environments/storage/docker.py", line 501, in create_dockerfile_object
    cloudpickle.dump(self._flows[flow_name], f)
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/cloudpickle/cloudpickle_fast.py", line 55, in dump
    CloudPickler(
  File "/Users/adyer/Desktop/git/pipelines/venv/lib/python3.8/site-packages/cloudpickle/cloudpickle_fast.py", line 563, in dump
    return Pickler.dump(self, obj)
TypeError: cannot pickle '_cffi_backend.FFI' object