SyntaxHighlighter Evolved base indentation

I’m using the SyntaxHighlighter Evolved plugin and it works great, except that the “base indentation level” is lost.
For example, while syntax highlighting something like this works fine:

def f():
    a = 1

when syntax highlighting a block that should be indented as a whole, that does not work:

return a

“return a” should be aligned with “a = 1”, but it appears at the beginning of the line instead.

This makes it impossible to annotate longer functions in several pieces.