import os
print(os.path.abspath('..'))
print(os.path.exists('/users'))
print(os.path.isdir('/users'))
os.path.join('/tmp/a','b/c')

from pathlib import Path
p=Path('.')
print(p.resolve())

p.is_dir()

q=Path('/tmp/a')
Path.mkdir(q,parents=True)

报错：
Traceback (most recent call last):
  File "/Users/name/PycharmProjects/geekbang10/dir_test.py", line 14, in <module>
    Path.mkdir(q,parents=True)
  File "/Users/name/anaconda3/envs/learn/lib/python3.7/pathlib.py", line 1251, in mkdir
    self._accessor.mkdir(self, mode)
FileExistsError: [Errno 17] File exists: '/tmp/a'