code: def popleft(self) -> T:
      assert len(self) > 0
      self.priority_sums.popleft()
      self.priority_mins.popleft()
      return self.data.popleft()
  
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 4 for calling the PrioritizedBuffer obj's underlying member method code with example usage: obj.popleft() and returns: self