diff --git a/internal.go b/internal.go
index d5a7c71..95b2a62 100644
--- a/internal.go
+++ b/internal.go
@@ -145,42 +145,6 @@ func hasSurroundingQuotes(value string) bool {
 	return first == last && (first == '"' || first == '\'' || first == '`')
 }
 
-func (ini *GoINI) save(data string) error {
-	if ini.filename == "" {
-		return errFilenameRequired
-	}
-	info, err := os.Stat(ini.filename)
-	if err != nil {
-		return err
-	}
-	return ini.saveFile(ini.filename, data, info.Mode().Perm())
-}
-
-func (ini *GoINI) saveFile(filename string, data string, perm os.FileMode) error {
-	if filename == "" {
-		return errFilenameRequired
-	}
-	perm = perm.Perm()
-	writePerm := perm | 0o200
-	if info, err := os.Stat(filename); err == nil {
-		if info.Mode().IsRegular() {
-			if err := os.Chmod(filename, writePerm); err != nil {
-				return err
-			}
-		}
-	} else if !errors.Is(err, os.ErrNotExist) {
-		return err
-	}
-	if err := os.WriteFile(filename, []byte(data), writePerm); err != nil {
-		return err
-	}
-	if err := os.Chmod(filename, perm); err != nil {
-		return err
-	}
-	ini.filename = filename
-	return nil
-}
-
 func (ini *GoINI) rebuildIndexes() {
 	ini.sectionKeys = make(map[string][]string)
 	ini.sectionOrder = nil
@@ -245,9 +209,6 @@ func (ini *GoINI) findSectionLineIndex(sectionName string) (int, bool) {
 }
 
 func (ini *GoINI) findSectionKeyLineIndex(sectionName string, keyName string) (int, bool) {
-	if ini.sectionKeyLineIndexes[sectionName] == nil {
-		return 0, false
-	}
 	index, ok := ini.sectionKeyLineIndexes[sectionName][keyName]
 	return index, ok
 }
@@ -375,7 +336,7 @@ func commentLines(comment string) []iniLine {
 
 func formatComment(comment string) string {
 	trimmed := strings.TrimLeftFunc(comment, unicode.IsSpace)
-	if strings.HasPrefix(trimmed, "#") || strings.HasPrefix(trimmed, ";") {
+	if isComment(trimmed) {
 		return comment
 	}
 	if comment == "" {
@@ -469,6 +430,42 @@ func formatINIComment(comment string) string {
 	return "# " + comment
 }
 
+func (ini *GoINI) save(data string) error {
+	if ini.filename == "" {
+		return errFilenameRequired
+	}
+	info, err := os.Stat(ini.filename)
+	if err != nil {
+		return err
+	}
+	return ini.saveFile(ini.filename, data, info.Mode().Perm())
+}
+
+func (ini *GoINI) saveFile(filename string, data string, perm os.FileMode) error {
+	if filename == "" {
+		return errFilenameRequired
+	}
+	perm = perm.Perm()
+	writePerm := perm | 0o200
+	if info, err := os.Stat(filename); err == nil {
+		if info.Mode().IsRegular() {
+			if err := os.Chmod(filename, writePerm); err != nil {
+				return err
+			}
+		}
+	} else if !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+	if err := os.WriteFile(filename, []byte(data), writePerm); err != nil {
+		return err
+	}
+	if err := os.Chmod(filename, perm); err != nil {
+		return err
+	}
+	ini.filename = filename
+	return nil
+}
+
 func matchStrings(items []string, match string) []string {
 	if match == "" {
 		return cloneStrings(items)