code: function isCallbackExpression(node, parentNode) {
  
              // ensure the parent node exists and is an expression
              if (!parentNode || parentNode.type !== "ExpressionStatement") {
                  return false;
              }
  
              // cb()
              if (parentNode.expression === node) {
                  return true;
              }
  
              // special case for cb && cb() and similar
              if (parentNode.expression.type === "BinaryExpression" || parentNode.expression.type === "LogicalExpression") {
                  if (parentNode.expression.right === node) {
                      return true;
                  }
              }
  
              return false;
          }
docs: Determines whether or not the callback is part of a callback expression.
  @param {ASTNode} node The callback node
  @param {ASTNode} parentNode The expression node
  @returns {boolean} Whether or not this is part of a callback expression