code: def __getitem__(self, index):
      out = None
      low = max(0, index.low)
      high = min(len(self.values) - 1, index.high)
      for i in range(low, high + 1):
          if out is None:
              out = self.values[i]
          else:
              out = out.union(self.values[i])
      return out or UNKNOWN_RANGE
  
imports: from math import isinf, isnan
  import itertools
  import numpy
label_desc: Use image node_id 6 for calling the IntervalTuple obj's underlying member method code with example usage: obj.__getitem__(index) and returns: unknown