diff --git a/.swift-version b/.swift-version
new file mode 100644
index 0000000..b883184
--- /dev/null
+++ b/.swift-version
@@ -0,0 +1 @@
+5.9
\ No newline at end of file
diff --git a/.swiftformat b/.swiftformat
index 24a794d..9857c7f 100644
--- a/.swiftformat
+++ b/.swiftformat
@@ -1,4 +1,3 @@
---swiftversion 5.7
 --exclude .build
 
 # rules
diff --git a/Sources/ScreamURITemplate/Internal/ValueFormatting.swift b/Sources/ScreamURITemplate/Internal/ValueFormatting.swift
index 3a6626e..3684f78 100644
--- a/Sources/ScreamURITemplate/Internal/ValueFormatting.swift
+++ b/Sources/ScreamURITemplate/Internal/ValueFormatting.swift
@@ -47,11 +47,10 @@ func percentEncode(string: String, withAllowedCharacters allowedCharacterSet: Ch
 
 extension StringProtocol {
     func formatForTemplateExpansion(variableSpec: VariableSpec, expansionConfiguration: ExpansionConfiguration) throws -> String {
-        let modifiedValue: String
-        if let prefixLength = variableSpec.prefixLength() {
-            modifiedValue = String(prefix(prefixLength))
+        let modifiedValue = if let prefixLength = variableSpec.prefixLength() {
+            String(prefix(prefixLength))
         } else {
-            modifiedValue = String(self)
+            String(self)
         }
         let encodedExpansion = try percentEncode(string: modifiedValue, withAllowedCharacters: expansionConfiguration.percentEncodingAllowedCharacterSet, allowPercentEncodedTriplets: expansionConfiguration.allowPercentEncodedTriplets)
         if expansionConfiguration.named {