Python Compile file(.pyc) generated even after errors in code-why?

Question

I have the below code in a file a1.py

fff
def test(arg):
        print 'sid'
        print arg
        print 'sid2'
test()

The above code contains 2 errors:

1. fff does not exist and is still being asked to print

2. Arguments are not passed in test()

Now i write an another file b1.py In that file the code is:

import a1
print 'b1 execution done'

Que 1: I executed b1.py and a1.pyc file is generated. Why ? There is a syntax error.pyc file should not have been generated?

Que2: Explain in laymen terms what is pyc file and what role does it play?

Que3: Why is pyc file generated even if a1.py has errors ?(e.g. argument not being passed)

Answer 1

Python automatically compiles your script to compiled code, so called byte code, before running it. When a module is imported for the first time, or when the source is more recent than the current compiled file, a .pyc file containing the compiled code will usually be created in the same directory as the .py file.