code: def _isInstalled(fullFname):
      
      if not fullFname: return False
      if not os.path.exists(fullFname): return False
      instAreas = []
      try:
          import site
          instAreas = site.getsitepackages()
      except:
          pass # python 2.6 and lower don't have site.getsitepackages()
      if len(instAreas) < 1:
          instAreas = [ os.path.dirname(os.__file__) ]
      for ia in instAreas:
          if fullFname.find(ia) >= 0:
              return True
      return False
docs: Return True if the given file name is located in an
      installed area (versus a user-owned file)