error on bat file

[snippsat]

py.exe get installed in Windows folder when install Python37.
Can be used to accessing previous version or current,can also install with pip to all version installed.
Example:

# Python version set in Windows Path
C:\>python -V
Python 3.7.0

# Can also access with py
C:\>py -3.7 -V
Python 3.7.0

# Older version i have
C:\>py -2.7 -V
Python 2.7.9

C:\>py -3.4 -V
Python 3.4.2

C:\>py -3.5 -V
Python 3.5.2

C:\>py -3.6 -V
Python 3.6.4

Use py to install with pip to eg 2.7.

λ py -2.7 -m pip install logzero                                                                               
Requirement already satisfied: logzero in c:\python27\lib\site-packages

Making bat hello.bat.
Use python main version,pause in bat so cmd window doesn't close immediately.
Can also put this last in code input('Press Enter to exit').

@echo off
python C:/foo/hello.py %*
pause

If want to run 2.7 in a bat file,then use py.

@echo off
py -2.7 C:/foo/hello.py %*
pause