Single line of code: [4 spaces and an escaped newline]
return [4 spaces and an escaped newline]
New paragraph [2 escaped newlines]

Code Block (no lang): [4 spaces and an escaped newline]

if this [4 spaces and an escaped newline]    
then [4 spaces and an escaped newline]    
that
else
the_other_thing [4 spaces and an escaped newline]    
endif

(no spaces before newlines for next block)

Code Block (python):

if this is not None:
    that
else:
    other_thing