I installed python-matploglib and python-mpltoolkits.basemap using apt, but when I tried to import Basemap using from mpltoolkits.basemap import Basemap, the following warning shows up:

usr/lib/pymodules/python2.7/mpl_toolkits/__init__.py:2: UserWarning: Module dap was already imported from None, but /usr/lib/python2.7/dist-packages is being added to sys.path
  __import__('pkg_resources').declare_namespace(__name__)

To resolve this warning, edit the file /usr/lib/python2.7/dist-packages/dap-2.2.6.7.egg-info/namespace_packages.txt, add dap as the first line.

dap
dap.plugins
dap.responses

Ref: Stackoverflow Question