Getting error trying to install pdfservices-sdk

I am trying to install the pdfservices-sdk, but it is breaking trying to build PyYaml.. see below

Collecting PyYAML==6.0

  Using cached PyYAML-6.0.tar.gz (124 kB)

  Installing build dependencies ... done

  Getting requirements to build wheel ... error

  error: subprocess-exited-with-error

  × Getting requirements to build wheel did not run successfully.

  │ exit code: 1

  ╰─> [48 lines of output]

      running egg_info

      writing lib/PyYAML.egg-info/PKG-INFO

      writing dependency_links to lib/PyYAML.egg-info/dependency_links.txt

      writing top-level names to lib/PyYAML.egg-info/top_level.txt

      Traceback (most recent call last):

        File "/Users/xxxx/Projects/envs/adobe/lib/python3.8/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>

          main()

        File "/Users/xxxx/Projects/envs/adobe/lib/python3.8/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main

          json_out['return_val'] = hook(**hook_input['kwargs'])

        File "/Users/xxxx/Projects/envs/adobe/lib/python3.8/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 118, in get_requires_for_build_wheel

          return hook(config_settings)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 355, in get_requires_for_build_wheel

          return self._get_build_requires(config_settings, requirements=['wheel'])

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 325, in _get_build_requires

          self.run_setup()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/build_meta.py", line 341, in run_setup

          exec(code, locals())

        File "<string>", line 288, in <module>

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/__init__.py", line 107, in setup

          return distutils.core.setup(**attrs)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/core.py", line 185, in setup

          return run_commands(dist)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/core.py", line 201, in run_commands

          dist.run_commands()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/dist.py", line 969, in run_commands

          self.run_command(cmd)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/dist.py", line 1233, in run_command

          super().run_command(command)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/dist.py", line 988, in run_command

          cmd_obj.run()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/command/egg_info.py", line 319, in run

          self.find_sources()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/command/egg_info.py", line 327, in find_sources

          mm.run()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/command/egg_info.py", line 549, in run

          self.add_defaults()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/command/egg_info.py", line 587, in add_defaults

          sdist.add_defaults(self)

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/command/sdist.py", line 113, in add_defaults

          super().add_defaults()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/command/sdist.py", line 251, in add_defaults

          self._add_defaults_ext()

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/command/sdist.py", line 336, in _add_defaults_ext

          self.filelist.extend(build_ext.get_source_files())

        File "<string>", line 204, in get_source_files

        File "/private/var/folders/h1/k2bjqmd526n6w5mn059n4z500000gn/T/pip-build-env-p_8xnrsz/overlay/lib/python3.8/site-packages/setuptools/_distutils/cmd.py", line 107, in __getattr__

          raise AttributeError(attr)

      AttributeError: cython_sources

      [end of output]

Have you seen this before? Any idea what the workaround might. be?