when i try to pip installi flask migrate.
getting this kind of error
Installing collected packages: Flask-SQLAlchemy, Flask-Script, Flask-Migrate Found existing installation: Flask-SQLAlchemy 0.16 Uninstalling Flask-SQLAlchemy-0.16:Exception:Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main status = self.run(options, args) File "/usr/local/lib/python2.7/dist-packages/pip/commands/install.py", line 317, in run prefix=options.prefix_path, File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 726, in install requirement.uninstall(auto_confirm=True) File "/usr/local/lib/python2.7/dist-packages/pip/req/req_install.py", line 746, in uninstall paths_to_remove.remove(auto_confirm) File "/usr/local/lib/python2.7/dist-packages/pip/req/req_uninstall.py", line 115, in remove renames(path, new_path) File "/usr/local/lib/python2.7/dist-packages/pip/utils/init.py", line 267, in renames shutil.move(old, new) File "/usr/lib/python2.7/shutil.py", line 303, in move os.unlink(src)OSError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/Flask_SQLAlchemy-0.16.dist-info/DESCRIPTION.rst'