diff --git a/packages/singly-linked-list/yarn.lock b/packages/singly-linked-list/yarn.lock
index 4272a2d..f600288 100644
--- a/packages/singly-linked-list/yarn.lock
+++ b/packages/singly-linked-list/yarn.lock
@@ -464,6 +464,11 @@ acorn-walk@^6.0.1:
   resolved "https://registry.yarnpkg.com/acorn-walk/-/acorn-walk-6.2.0.tgz#123cb8f3b84c2171f1f7fb252615b1c78a6b1a8c"
   integrity sha512-7evsyfH1cLOCdAzZAd43Cic04yKydNx0cF+7tiA19p1XnLLPU4dpCQOqpjqwokFe//vS0QqfqqjCS2JkiIs0cA==
 
+acorn@7.4.1, acorn@^7.0.0:
+  version "7.4.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.4.1.tgz#feaed255973d2e77555b83dbc08851a6c63520fa"
+  integrity sha512-nQyp0o1/mNdbTO1PO6kHkwSrmgZ0MT/jCCpNiwbUjGoRN4dlBhqJtoQuCnEOKzgTVwg0ZWiCoQy6SxMebQVh8A==
+
 acorn@^5.5.3:
   version "5.7.3"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.3.tgz#67aa231bf8812974b85235a96771eb6bd07ea279"
@@ -474,11 +479,6 @@ acorn@^6.0.1:
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.3.0.tgz#0087509119ffa4fc0a0041d1e93a417e68cb856e"
   integrity sha512-/czfa8BwS88b9gWQVhc8eknunSA2DoJpJyTQkhheIf5E48u1N0R4q/YxxsAeqRrmK9TQ/uYfgLDfZo91UlANIA==
 
-acorn@^7.0.0:
-  version "7.0.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.0.0.tgz#26b8d1cd9a9b700350b71c0905546f64d1284e7a"
-  integrity sha512-PaF/MduxijYYt7unVGRuds1vBC9bFxbNf+VWqhOClfdgy7RlVkQqt610ig1/yxTgsDIfW1cWDel5EBbOy3jdtQ==
-
 ajv@^6.10.0, ajv@^6.10.2, ajv@^6.5.5:
   version "6.10.2"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.10.2.tgz#d3cea04d6b017b2894ad69040fec8b623eb4bd52"