class_docstr: A logical variable with a constraint.
  
  These will unify with other `Var`s regardless of the constraints.
class_docstr_tok: ["A","logical","variable","with","a","constraint",".","These","will","unify","with","other","`","Var","`","s","regardless","of","the","constraints","."]
code: def __str__(self):
      return f"~{self.token} [{self.constraint}]"
  
imports: from collections.abc import Mapping
  from numbers import Number
  from typing import Optional, Union
  import numpy
  from cons.core import ConsError, _car, _cdr
  from etuples import apply, etuple, etuplize
  from etuples.core import ExpressionTuple
  from unification.core import _unify, assoc
  from unification.utils import transitive_get
  from unification.variable import Var, isvar, var
  from pytensor.graph.basic import Constant, Variable
  from pytensor.graph.op import Op
  from pytensor.graph.type import Type
label_desc: Use image node_id 4 for calling the ConstrainedVar obj's underlying member method code with example usage: obj.__str__() and returns: str, self, str, self, str