Added Graphviz too Path but pydot cannot find dot excuable correctly

I use anaconda python on windows 10 platform, install pydot by

pip install pydot then install Graphviz by install package download from https://www.graphviz.org/download/. and then add the install location to Path: E:\Program Files (x86)\Graphviz2.38\bin but pydot cannot find dot excuable correctly because of the code in pydot below as I think:

def get_executable_extension():
    # type: () -> str
    if is_windows():
        return '.bat' if is_anacoda() else '.exe'
    else:
        return ''

There are not excuable file name dot.bat, only dot.exe in my path. Even I use anaconda, but I am not install graphviz by conda. And the error info is confusing： FileNotFoundError: [WinError 2] "dot" not found in path. Pydot just can not find dot.bat but not dot.

[QingGo]

Finally, I use

conda install -c anaconda graphviz

to install graphviz and then everything going well.

[prmtl]

Yes, pydot installed via conda it supports graphviz installed by conda only.

I agree that the error message should take different installation methods into account and be improved.