docs: function traverseAst(sourceCode, node, parent, visitor) {
      if (visitor[node.type]) {
          visitor[node.type](node, parent)
      }
  
      const keys = sourceCode.visitorKeys[node.type]
      for (const key of keys) {
          const child = node[key]
  
          if (Array.isArray(child)) {
              for (const c of child) {
                  if (c) {
                      traverseAst(sourceCode, c, node, visitor)
                  }
              }
          } else if (child) {
              traverseAst(sourceCode, child, node, visitor)
          }
      }
  }