docs: PyExpr exec(CallNode callNode, LocalVariableStack localVarStack, ErrorReporter errorReporter) {
      this.localVarStack = localVarStack;
      this.errorReporter = errorReporter;
      PyExpr callExpr = visit(callNode);
      this.localVarStack = null;
      this.errorReporter = null;
      return callExpr;
    }