diff --git a/src/ui/bigtext/line.py b/src/ui/bigtext/line.py
index 11b794b..1929757 100644
--- a/src/ui/bigtext/line.py
+++ b/src/ui/bigtext/line.py
@@ -36,12 +36,12 @@ class Line:
         prefix_chars = prefix_bytes.decode("utf8", errors="ignore")
         return len(prefix_chars)
 
-    def line_prepared_for_display(self):
+    def line_prepared_for_display(self) -> str:
         line = self._line_tabs_replaced()
         line = self._replace_control_chars_with_pictures(line)
         return line
 
-    def _replace_control_chars_with_pictures(self, line: str):
+    def _replace_control_chars_with_pictures(self, line: str) -> str:
         length = len(line)
         for i in range(length):
             c = line[i]
@@ -58,7 +58,7 @@ class Line:
 
         return line;
 
-    def _line_tabs_replaced(self):
+    def _line_tabs_replaced(self) -> str:
         line = self._line;
         i = 0
         offset = 0
diff --git a/src/ui/bigtext/logFileModel.py b/src/ui/bigtext/logFileModel.py
index 0050128..21e7bfd 100644
--- a/src/ui/bigtext/logFileModel.py
+++ b/src/ui/bigtext/logFileModel.py
@@ -53,13 +53,13 @@ class LogFileModel:
             is_regex=is_regex,
             hit_background_color="ffff00")
 
-    def get_tab_name(self):
+    def get_tab_name(self) -> str:
         file_name = os.path.basename(self._file)
         if len(file_name) > 35:
             file_name = file_name[:15] + "..." + file_name[-15:]
         return file_name
 
-    def read_range(self, start_byte: int, end_byte: int):
+    def read_range(self, start_byte: int, end_byte: int) -> str:
         # with self._lock:
         if True:
             with open(self._file, 'rb') as f: