code: def get_precomputes(self, mapping):
      precomputes = {}
      if self.min_val is None:
          precomputes["min_val"] = hl.agg.min(mapping.x)
      if self.max_val is None:
          precomputes["max_val"] = hl.agg.max(mapping.x)
      return hl.struct(**precomputes)
  
imports: from typing import List
  import abc
  from pandas import DataFrame
  import pandas
  import hail
  from hail.utils.java import warning
  from .utils import should_use_scale_for_grouping
label_desc: Use image node_id 2 for calling the StatBin obj's underlying member method code with example usage: obj.get_precomputes(mapping) and returns: hl