Is There A Function I Can Use To Get Rid Of The Blank Lines In My XML File?

I have 33 blank line in my sitemap.xml file on all of my subsites at (as an example, view

This is causing the rendering error:

This page contains the following errors:

error on line 33 at column 6: XML declaration allowed only at the start of the document

Below is a rendering of the page up to the first error.

Viewing the source of the page, I can see the sitemap – beginning at line 33

Is there a line I can add to the plugin, or a function available that would get rid of these blank lines in my sitemap?