code: def envCheckFlag(self, name, default = False):
          
          if self._flags.has_key(name):
              return self._flags[name]
          else:
              val = self._env.get(name)
              if val is None:
                  return default
              elif val.lower() in ['yes', 'on']:
                  self._flags[name] = True
                  return True
              elif val.lower() in ['no', 'off']:
                  self._flags[name] = False
                  return False
              else:
                  raise AttributeError("Value for flag %s, must be yes, no, on or off" 
                                       % name)
docs: Check graph flag for enabling / disabling attributes through
          the use of <name> environment variable.
          
          @param name:    Name of flag.
                          (Also determines the environment variable name.)
          @param default: Boolean (True or False). Default value for flag.
          @return:        Return True if the flag is enabled.