Implementation to pass test

pre_commit_hooks/end_of_file_fixer.py

@@ -20,9 +20,13 @@ def fix_file(file_obj: IO[bytes]) -> int:
     last_character = file_obj.read(1)
     # last_character will be '' for an empty file
     if last_character not in {LF, CR} and last_character != b'':
+        # Check if file uses CRLF endings
+        file_obj.seek(0, os.SEEK_SET)
+        content = file_obj.read()
+        ending = CRLF if CRLF in content else LF
         # Needs this seek for windows, otherwise IOError
         file_obj.seek(0, os.SEEK_END)
-        file_obj.write(LF)
+        file_obj.write(ending)
         return 1
 
     while last_character in {LF, CR}: