diff --git a/masque/file/dxf.py b/masque/file/dxf.py
index 7ae4b6d..581bfcd 100644
--- a/masque/file/dxf.py
+++ b/masque/file/dxf.py
@@ -34,6 +34,7 @@ DEFAULT_LAYER = 'DEFAULT'
 
 def write(pattern: Pattern,
           stream: io.TextIOBase,
+          *,
           modify_originals: bool = False,
           dxf_version='AC1024',
           disambiguate_func: Callable[[Iterable[Pattern]], None] = None):
diff --git a/masque/file/gdsii.py b/masque/file/gdsii.py
index 7192ecc..df23293 100644
--- a/masque/file/gdsii.py
+++ b/masque/file/gdsii.py
@@ -54,6 +54,7 @@ def build(patterns: Union[Pattern, List[Pattern]],
           meters_per_unit: float,
           logical_units_per_unit: float = 1,
           library_name: str = 'masque-gdsii-write',
+          *,
           modify_originals: bool = False,
           disambiguate_func: Callable[[Iterable[Pattern]], None] = None,
           ) -> gdsii.library.Library:
diff --git a/masque/file/svg.py b/masque/file/svg.py
index 0ce5750..b719b0b 100644
--- a/masque/file/svg.py
+++ b/masque/file/svg.py
@@ -12,8 +12,8 @@ from .. import Pattern
 
 
 def writefile(pattern: Pattern,
-          filename: str,
-          custom_attributes: bool=False):
+              filename: str,
+              custom_attributes: bool=False):
     """
     Write a Pattern to an SVG file, by first calling .polygonize() on it
      to change the shapes into polygons, and then writing patterns as SVG