diff --git a/build.py b/build.py
index c610bae40..66c4d1ca0 100644
--- a/build.py
+++ b/build.py
@@ -37,7 +37,10 @@ def get_entry_point(filename: Path, prefix: str, import_path: str) -> List[str]:
     tree = ast.parse(contents)
     # Find root functions named "run"
     has_run = any(
-        x for x in tree.body if isinstance(x, ast.FunctionDef) and x.name == "run"
+        x
+        for x in tree.body
+        if (isinstance(x, ast.FunctionDef) and x.name == "run")
+        or (isinstance(x, ast.ImportFrom) and "run" in [a.name for a in x.names])
     )
     if not has_run:
         return []
diff --git a/newsfragments/739.misc b/newsfragments/739.misc
new file mode 100644
index 000000000..b695ba18f
--- /dev/null
+++ b/newsfragments/739.misc
@@ -0,0 +1 @@
+Add any2nexus to formal dispatcher mechanisms.
diff --git a/src/dxtbx/format/nxmx_writer.py b/src/dxtbx/format/nxmx_writer.py
index 0c1768b77..57cfce018 100644
--- a/src/dxtbx/format/nxmx_writer.py
+++ b/src/dxtbx/format/nxmx_writer.py
@@ -820,7 +820,7 @@ def add_crystal(self, multi_crystal_group_name, crystal):
         )
 
 
-def run(args):
+def run(args: list[str] | None = None):
     usage = "dials.python nxmx_writer.py <experiments OR image files>"
     parser = ArgumentParser(
         usage=usage,