def visitConcatenation(self, ctx):
        """
        expression: expression AMPERSAND expression
        """
        arg1 = conversions.to_string(self.visit(ctx.expression(0)), self._eval_context)
        arg2 = conversions.to_string(self.visit(ctx.expression(1)), self._eval_context)
        return arg1 + arg2
def visitConcatenation ( self , ctx ) : arg1 = conversions . to_string ( self . visit ( ctx . expression ( 0 ) ) , self . _eval_context ) arg2 = conversions . to_string ( self . visit ( ctx . expression ( 1 ) ) , self . _eval_context ) return arg1 + arg2
expression: expression AMPERSAND expression