diff --git a/meshpy/inputfile.py b/meshpy/inputfile.py
index cc883288..3c156e7b 100644
--- a/meshpy/inputfile.py
+++ b/meshpy/inputfile.py
@@ -655,7 +655,7 @@ def delete_section(self, section_name):
         else:
             raise Warning("Section {} does not exist!".format(section_name))
 
-    def write_input_file(self, file_path, nox_xml_file=None, **kwargs):
+    def write_input_file(self, file_path, *, nox_xml_file=None, **kwargs):
         """
         Write the input to a file.
 
@@ -691,6 +691,7 @@ def write_input_file(self, file_path, nox_xml_file=None, **kwargs):
 
     def get_dat_lines(
         self,
+        *,
         header=True,
         dat_header=True,
         add_script_to_header=True,