code: def open_fs(
          self,
          fs_url,  # type: Union[FS, Text]
          writeable=False,  # type: bool
          create=False,  # type: bool
          cwd=".",  # type: Text
          default_protocol="osfs",  # type: Text
      ):
          # type: (...) -> FS
          
          from ..base import FS
  
          if isinstance(fs_url, FS):
              _fs = fs_url
          else:
              _fs, _path = self.open(
                  fs_url,
                  writeable=writeable,
                  create=create,
                  cwd=cwd,
                  default_protocol=default_protocol,
              )
          return _fs
docs: Open a filesystem from a FS URL (ignoring the path component).
  
          Arguments:
              fs_url (str): A filesystem URL.
              writeable (bool, optional): `True` if the filesystem must
                  be writeable.
              create (bool, optional): `True` if the filesystem should be
                  created if it does not exist.
              cwd (str): The current working directory (generally only
                  relevant for OS filesystems).
              default_protocol (str): The protocol to use if one is not
                  supplied in the FS URL (defaults to ``"osfs"``).
  
          Returns:
              ~fs.base.FS: A filesystem instance.