The isabs() function is defined in the path sub-module of the os module. It is used to determine whether a given pathname represents an absolute path or not. 

An absolute path is one that begins from the root directory of a file system, regardless of the current working directory. In a Unix-like system, an absolute path starts with a forward slash ('/'), while a relative path doesn't.

To use the function, we first need to import it in our program as follows.

from os.path import isabs

The function returns a boolean value, True if the path is an absolute path and False otherwise. It does not validate whether the path actually exists.

#import the function
from os.path import isabs

paths = ['/', '/temp/usr', 'images/me.jpg', '/home/files', 'desktop/project/', '/users/john']
for p in paths:
    if isabs(p):

In the above example, we have a list of paths, we used a for loop to iterate over the paths calling  the isabs() function during each iteration. Only the absolute paths are printed.