ENH: Permit XmlSerializable.to_xml() to pass kwargs to ElementTree.tostring()

Author: effigies

nibabel/gifti/gifti.py

@@ -834,12 +834,12 @@ def _to_xml_element(self):
             GIFTI.append(dar._to_xml_element())
         return GIFTI
 
-    def to_xml(self, enc='utf-8') -> bytes:
+    def to_xml(self, enc='utf-8', **kwargs) -> bytes:
         """Return XML corresponding to image content"""
         header = b"""<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE GIFTI SYSTEM "http://www.nitrc.org/frs/download.php/115/gifti.dtd">
 """
-        return header + super().to_xml(enc)
+        return header + super().to_xml(enc, **kwargs)
 
     # Avoid the indirection of going through to_file_map
     def to_bytes(self, enc='utf-8'):

nibabel/xmlutils.py

@@ -24,11 +24,11 @@ def _to_xml_element(self):
         """Output should be a xml.etree.ElementTree.Element"""
         raise NotImplementedError()
 
-    def to_xml(self, enc='utf-8'):
+    def to_xml(self, enc='utf-8', **kwargs):
         """Output should be an xml string with the given encoding.
         (default: utf-8)"""
         ele = self._to_xml_element()
-        return '' if ele is None else tostring(ele, enc)
+        return '' if ele is None else tostring(ele, enc, **kwargs)
 
 
 class XmlBasedHeader(FileBasedHeader, XmlSerializable):