diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 50032cc..356ed40 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -20,7 +20,7 @@ repos:
     - id: trailing-whitespace
 
 -   repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: "v0.8.6"
+    rev: "v0.9.9"
     hooks:
     - id: ruff
       args: ["--fix", "--show-fixes"]
diff --git a/src/pylhe/__init__.py b/src/pylhe/__init__.py
index e185f39..19732e2 100644
--- a/src/pylhe/__init__.py
+++ b/src/pylhe/__init__.py
@@ -248,7 +248,7 @@ def _indent(elem, level=0):
 class LHEInit(dict):
     """Store the <init> block as dict."""
 
-    fieldnames = ["initInfo", "procInfo" "weightgroup", "LHEVersion"]
+    fieldnames = ["initInfo", "procInfoweightgroup", "LHEVersion"]
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -377,9 +377,7 @@ def write(self, output_stream, rwgt=True, weights=False):
         """
         Write the LHE file to an output stream.
         """
-        output_stream.write(
-            f"<LesHouchesEvents version=\"{self.init['LHEVersion']}\">\n"
-        )
+        output_stream.write(f'<LesHouchesEvents version="{self.init["LHEVersion"]}">\n')
         output_stream.write(self.init.tolhe() + "\n")
         for e in self.events:
             output_stream.write(e.tolhe(rwgt=rwgt, weights=weights) + "\n")