graphviz dot command not found

I got trouble with the **graphviz** python library.
Apparently graphviz should be already included in a-Shell.
When I try to install it, it says 'Requirements already satisfied'.
But when I try to use the main command line tool of graphviz, '**dot**', it says that it does't find it.
I even installed **pydot** separately, but the result is the same.

```
[~cloud]$
[~cloud]$ pip -v install graphviz
Using pip 22.2 from /var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/pip (python 3.9)
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: graphviz in /private/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages (0.20.1
)
[~cloud]$
[~cloud]$ dot --help
dot: command not found
[~cloud]$ python dot
python3: can't open file '/private/var/mobile/Library/Mobile Documents/iCloud~AsheKube~app~a-Shell/Documents/dot': [Errno 2] No such file or directory
[~cloud]$ python dot.py
python3: can't open file '/private/var/mobile/Library/Mobile Documents/iCloud~AsheKube~app~a-Shell/Documents/dot.py': [Errno 2] No such file or directory
[~cloud]$ python -m dot.py
/private/var/containers/Bundle/Application/38DB70EF-E2C8-431C-BCDA-60CA2AB58FF3/a-Shell-mini.app/Library/bin/python3: Error while finding module specification for 'dot.py'
(ModuleNotFoundError: No module named 'dot'). Try using 'dot' instead of 'dot.py' as the module name.
[~cloud]$ python -m dot
/private/var/containers/Bundle/Application/38DB70EF-E2C8-431C-BCDA-60CA2AB58FF3/a-Shell-mini.app/Library/bin/python3: No module named dot
[~cloud]$
[~cloud]$ pip -v install pydot
Using pip 22.2 from /var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/pip (python 3.9)
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: pydot in /private/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages (1.4.2)
Requirement already satisfied: pyparsing>=2.1.4 in /private/var/containers/Bundle/Application/38DB70EF-E2C8-431C-BCDA-60CA2AB58FF3/a-Shell-mini.app/Library/lib/python3.9/s
ite-packages (from pydot) (3.0.9)
[~cloud]$
[~cloud]$ dot
dot: command not found
[~cloud]$ python -m dot
/private/var/containers/Bundle/Application/38DB70EF-E2C8-431C-BCDA-60CA2AB58FF3/a-Shell-mini.app/Library/bin/python3: No module named dot
[~cloud]$
```

Even if I try to use graphviz in my code as a library, it gives me this error:
```
[~cloud]$ python example_diagram.py
Traceback (most recent call last):
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/backend/execute.py", line 91, in run_check
proc.check_returncode()
File "/private/var/containers/Bundle/Application/38DB70EF-E2C8-431C-BCDA-60CA2AB58FF3/a-Shell-mini.app/Library/lib/python3.9/subprocess.py", line 460, in check_returncode
raise CalledProcessError(self.returncode, self.args, self.stdout,
subprocess.CalledProcessError: Command '[PosixPath('dot'), '-Kdot', '-Tsvg', '-O', 'advanced_web_service_with_on-premise_(colored)']' returned non-zero exit status 127.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/private/var/mobile/Library/Mobile Documents/iCloud~AsheKube~app~a-Shell/Documents/example_diagram.py", line 36, in
ingress >> Edge(color="darkgreen") << grpcsvc >> Edge(color="darkorange") >> aggregator
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/diagrams/__init__.py", line 154, in __exit__
self.render()
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/diagrams/__init__.py", line 188, in render
self.dot.render(format=self.outformat, view=self.show, quiet=True)
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/_tools.py", line 171, in wrapper
return func(*args, **kwargs)
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/rendering.py", line 122, in render
rendered = self._render(*args, **kwargs)
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/_tools.py", line 171, in wrapper
return func(*args, **kwargs)
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/backend/rendering.py", line 324, in render
execute.run_check(cmd,
File "/var/mobile/Containers/Data/Application/A5D5544D-8985-43D8-A812-B241A1D0BD6B/Library/lib/python3.9/site-packages/graphviz/backend/execute.py", line 93, in run_check
raise CalledProcessError(*e.args)
graphviz.backend.execute.CalledProcessError: Command '[PosixPath('dot'), '-Kdot', '-Tsvg', '-O', 'advanced_web_service_with_on-premise_(colored)']' returned non-zero exit
status 127. [stderr: b'dot: command not found\n']
[~cloud]$
```

Any clue?