>>> import os
>>> import random
>>> 
>>> def f(path, n):
...     exts = ('txt', 'mp3', 'html', 'jpg')
...     for i in range(n):
...         fname = 'name{}.{}'.format(i, random.choice(exts))
...         yield os.path.join(path, fname)
... 
>>> list(f('/a/b/c', 10))
['/a/b/c/name0.jpg', '/a/b/c/name1.jpg', '/a/b/c/name2.jpg', '/a/b/c/name3.html', '/a/b/c/name4.txt', '/a/b/c/name5.jpg', '/a/b/c/name6.txt', '/a/b/c/name7.jpg', '/a/b/c/name8.txt', '/a/b/c/name9.txt']
>>> list(f('/a/b/c/d', 5))
['/a/b/c/d/name0.mp3', '/a/b/c/d/name1.html', '/a/b/c/d/name2.jpg', '/a/b/c/d/name3.html', '/a/b/c/d/name4.html']
>>>

#!/usr/bin/env python3
 
import os
import random
 
def f(path, n):
    exts = ('txt', 'mp3', 'html', 'jpg')
    for i in range(n):
        fname = 'name{}.{}'.format(i, random.choice(exts))
        yield os.path.join(path, fname)
 
def main():
    print(list(f('/a/b/c', 10)))
    print(list(f('/a/b/c/d', 5)))
 
if __name__ == '__main__':
    main()