class_docstr: Represents a set of return edges.
  
  All return edges in an interval induce a same constraint on the contained
  edges, which means that all edges must either have a left orientation or
  all edges must have a right orientation.
class_docstr_tok: ["Represents","a","set","of","return","edges",".","All","return","edges","in","an","interval","induce","a","same","constraint","on","the","contained","edges",",","which","means","that","all","edges","must","either","have","a","left","orientation","or","all","edges","must","have","a","right","orientation","."]
code: def __init__(self, low=None, high=None):
      self.low = low
      self.high = high
  
imports: from collections import defaultdict
  import networkx
label_desc: Use image node_id 1 to create a new Interval object  with example: obj = Interval(low, high)