#NEWLINE# def equiv( self , other , prover = None ) : #NEWLINE# #INDENT# '\n        Check for logical equivalence.\n        Pass the expression (self <-> other) to the theorem prover.\n        If the prover says it is valid, then the self and other are equal.\n\n        :param other: an ``DrtExpression`` to check equality against\n        :param prover: a ``nltk.inference.api.Prover``\n        ' #NEWLINE# assert isinstance ( other , DrtExpression ) #NEWLINE# f1 = self . simplify ( ) . fol ( ) #NEWLINE# f2 = other . simplify ( ) . fol ( ) #NEWLINE# return f1 . equiv ( f2 , prover )