Installaing Package on Multiple versions of installation

[snippsat]

You can call diffident version of pip version like this(Windows).
For running python from different version py -2.7 my_prog.py using Python 2.7.
Running python 3.6 python my_prog.py.

C:\
λ py -2.7 -m pip -V
pip 9.0.1 from C:\Python27\lib\site-packages (python 2.7)

C:\
λ py -3.6 -m pip -V
pip 9.0.1 from C:\Python36\lib\site-packages (python 3.6)

I have Python 3.6 as main version,so that what's set in environment Path.                                                        

C:\                                                       
λ pip -V                                                  
pip 9.0.1 from c:\python36\lib\site-packages (python 3.6)

C:\
λ python
Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 17:54:52) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

If i want to install to Pytnon 2.7.

C:\
λ py -2.7 -m pip install requests
Collecting requests
  Using cached requests-2.13.0-py2.py3-none-any.whl
Installing collected packages: requests
Successfully installed requests-2.13.0

For 3.6 is just.

C:\
λ pip install requests
Requirement already satisfied: requests in c:\python36\lib\site-packages