我正在尝试安装Flask，但是我打赌所有这些警告和错误：

alex@alex-K43U:~/flask$ pip install Flask
Downloading/unpacking Flask
  Downloading Flask-0.9.tar.gz (481Kb): 481Kb downloaded
  Running setup.py egg_info for package Flask

    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'
Downloading/unpacking Werkzeug>=0.7 (from Flask)
  Downloading Werkzeug-0.8.3.tar.gz (1.1Mb): 1.1Mb downloaded
  Running setup.py egg_info for package Werkzeug

    warning: no files found matching '*' under directory 'werkzeug/debug/templates'
    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'
Downloading/unpacking Jinja2>=2.4 (from Flask)
  Downloading Jinja2-2.6.tar.gz (389Kb): 389Kb downloaded
  Running setup.py egg_info for package Jinja2

    warning: no previously-included files matching '*' found under directory 'docs/_build'
    warning: no previously-included files matching '*.pyc' found under directory 'jinja2'
    warning: no previously-included files matching '*.pyc' found under directory 'docs'
    warning: no previously-included files matching '*.pyo' found under directory 'jinja2'
    warning: no previously-included files matching '*.pyo' found under directory 'docs'
Installing collected packages: Flask, Werkzeug, Jinja2
  Running setup.py install for Flask

    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'
    error: could not create '/usr/local/lib/python2.7/dist-packages/flask': Permission denied
    Complete output from command /usr/bin/python -c "import setuptools;__file__='/home/alex/flask/build/Flask/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --single-version-externally-managed --record /tmp/pip-KD7NsY-record/install-record.txt:
    running install

running build

(a lot of creating and building)

error: could not create '/usr/local/lib/python2.7/dist-packages/flask': Permission denied

有解决这个问题的建议吗？

我正在使用ubuntu 11.10。