python pip安装flask时出现：warning: no previously-included files matching...？

Question

pip install flask时，出现如下警告信息，什么原因？表示什么意思呢？

warning: no files found matching '*' under directory 'tests'
warning: no previously-included files matching '*.pyc' found under directory 'docs'
warning: no previously-included files matching '*.pyo' found under directory 'docs'
warning: no previously-included files matching '*.pyc' found under directory 'tests'
warning: no previously-included files matching '*.pyo' found under directory 'tests'
warning: no previously-included files matching '*.pyc' found under directory 'examples'
warning: no previously-included files matching '*.pyo' found under directory 'examples'
no previously-included directories found matching 'docs/_build'
no previously-included directories found matching 'docs/_themes/.git'

Answer 1

Is it a permissions issue? Can you put the permissions of the directories involved in the installation and take a look? ls -l