docs: def _compose(self, name, args, mkdir=True):
          """Get a named filesystem entry, and extend it into a path with additional
          path arguments"""
          from os.path import normpath
          from ambry.dbexceptions import ConfigurationError
  
          root = p = self._config.filesystem[name].format(root=self._root)
  
          if args:
              args = [e.strip() for e in args]
              p = join(p, *args)
  
          if not isdir(p) and mkdir:
              makedirs(p)
  
          p = normpath(p)
  
          if not p.startswith(root):
              raise ConfigurationError("Path for name='{}', args={} resolved outside of define filesystem root"
                                   .format(name, args))
  
          return p