class_docstr: This class represents a constraint of the form (L =< N),
  where L is a label and N is a node (a label or a hole).
class_docstr_tok: ["This","class","represents","a","constraint","of","the","form","(","L","=","<","N",")",",","where","L","is","a","label","and","N","is","a","node","(","a","label","or","a","hole",")","."]
code: def __init__(self, lhs, rhs):
      self.lhs = lhs
      self.rhs = rhs
  
imports: from functools import reduce
  from nltk.parse import load_parser
  from nltk.sem.logic import AllExpression, AndExpression, ApplicationExpression, ExistsExpression, IffExpression, ImpExpression, LambdaExpression, NegatedExpression, OrExpression
  from nltk.sem.skolemize import skolemize
label_desc: Use image node_id 1 to create a new Constraint object  with example: obj = Constraint(lhs, rhs)