QGIS » QGIS Application

in my plugin I want to install python plugin to local repository.
folowing is the QGIS python console output.

import pip
pip.main(['install','pyxform','--user'])
Traceback (most recent call last):
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\basecommand.py", line 215, in main
status = self.run(options, args)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\commands\install.py", line 335, in run
wb.build(autobuilding=True)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\wheel.py", line 749, in build
self.requirement_set.prepare_files(self.finder)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\req\req_set.py", line 380, in prepare_files
ignore_dependencies=self.ignore_dependencies))
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\req\req_set.py", line 620, in prepare_file
session=self.session, hashes=hashes)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\download.py", line 821, in unpack_url
hashes=hashes
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\download.py", line 659, in unpack_http_url
hashes)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\download.py", line 882, in _download_http_url
_download_url(resp, link, content_file, hashes)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\download.py", line 585, in _download_url
progress_indicator = DownloadProgressBar(max=total_length).iter
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\utils\ui.py", line 158, in init
super(WindowsMixin, self)._init__(*args, **kwargs)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\utils\ui.py", line 82, in init
super(InterruptibleMixin, self).__init__(*args, **kwargs)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\utils\ui.py", line 118, in init
super(DownloadProgressMixin, self).__init__(*args, **kwargs)
File "C:\PROGRA~1\QGIS3~1.0\apps\Python36\lib\site-packages\pip\_vendor\progress\helpers.py", line 58, in init
if self.file.isatty() and self.hide_cursor:
AttributeError: 'NoneType' object has no attribute 'isatty'
```