Graphviz has been downloaded and written into the environment variables, but still prompts an error

Graphviz has been downloaded and written into environment variables, and has also entered pip install graphviz, pip install pydot, and still report errors:

`pydot` failed to call GraphViz.Please install GraphViz (https://www.graphvi.org)... 

Correction method: do not use pip install graphviz, use conda install graphviz to solve

#在anaconda prompt中依次输入：
pip uninstall graphviz
conda install graphviz