diff --git a/rednose/helpers/__init__.py b/rednose/helpers/__init__.py
index b2beede..3acc14a 100644
--- a/rednose/helpers/__init__.py
+++ b/rednose/helpers/__init__.py
@@ -9,8 +9,10 @@ def write_code(folder, name, code, header):
   if not os.path.exists(folder):
     os.mkdir(folder)
 
-  open(os.path.join(folder, f"{name}.cpp"), 'w', encoding='utf-8').write(code)
-  open(os.path.join(folder, f"{name}.h"), 'w', encoding='utf-8').write(header)
+  with open(os.path.join(folder, f"{name}.cpp"), 'w', encoding='utf-8') as f:
+    f.write(code)
+  with open(os.path.join(folder, f"{name}.h"), 'w', encoding='utf-8') as f:
+    f.write(header)
 
 
 def load_code(folder, name):
diff --git a/rednose/helpers/ekf_sym.py b/rednose/helpers/ekf_sym.py
index e8bd642..d0a8043 100644
--- a/rednose/helpers/ekf_sym.py
+++ b/rednose/helpers/ekf_sym.py
@@ -210,8 +210,10 @@ def gen_code(folder, name, f_sym, dt_sym, x_sym, obs_eqs, dim_x, dim_err, eskf_p
   if not os.path.exists(folder):
     os.mkdir(folder)
 
-  open(os.path.join(folder, f"{name}.h"), 'w', encoding='utf-8').write(header)  # header is used for ffi import
-  open(os.path.join(folder, f"{name}.cpp"), 'w', encoding='utf-8').write(code)
+  with open(os.path.join(folder, f"{name}.h"), 'w', encoding='utf-8') as f:
+    f.write(header)  # header is used for ffi import
+  with open(os.path.join(folder, f"{name}.cpp"), 'w', encoding='utf-8') as f:
+    f.write(code)
 
 
 class EKF_sym():