python cannot be called from the c drive

I want to install a compressed package in the package directory corresponding to python, that is, gtr-0.1.1.tar.gz. I need to unzip it, go into the Dos window under the package directory, and
Execute python setpu.py install
C:\Users\user\AppData\Local\Programs\Python\Python39\Lib\site-packages\gtr-0.1.1
but this directory cannot call python
'python'Not an internal or external command, nor a runnable program
or batch file.
I tried it and it seems that python cannot be called from the C drive. Normally win+R and then cmd can call python, and python is also on top in the system variable.