Add type annotation support with mypy

Default target in Makefile check types now.

1 files changed, 3 insertions, 3 deletions

diff --git a/blog/render.py b/blog/render.py
index 4e26318..cdd018f 100644
--- a/blog/render.py
+++ b/blog/render.py
@@ -1,16 +1,16 @@
 import markdown
 
 
-def read_file_content(filename):
+def read_file_content(filename: str) -> str:
     with open(filename) as f:
         return f.read()
 
 
-def write_file_content(filename, data):
+def write_file_content(filename: str, data: str) -> None:
     with open(filename, mode='w') as f:
         f.write(data)
 
 
-def to_html(filename):
+def to_html(filename: str) -> str:
     text = read_file_content(filename)
     return markdown.markdown(text, extensions=["fenced_code", "footnotes"])