code: def min(self) -> float:
      if self.length == 0:
          return np.inf
      else:
          return self.root[2]
  
imports: import collections
  from typing import Any, Callable, Deque, Generic, List, Optional, Sequence, Tuple, TypeVar
  import numpy
  from pfrl.utils.random import sample_n_k
label_desc: Use image node_id 2 for calling the MinTreeQueue obj's underlying member method code with example usage: obj.min() and returns: np, self