Absolute and Relative directory

Absolute directory and Relative directory

import os
print(ps.path.abspath('.'))
print(ps.path.abspath('..'))

If we have a file b.py in /home/a , how can I import b.py to my file?
There are three solutions we can use.
1)

import sys
sys.path.append("/home/a/")
import b 

from home.a.b import *

in home/ and a/ we must add init.py file.
3)
Add __init __.py(can keep empty) into the file.

Import home.a.b