Two-column portfile guidelines

[Ryan Schmidt]

On the topic of arranging a Portfile into two columns, the Guide says:

http://guide.macports.org/#development.practices.portstyle

Frequently multiple items are necessary in the second column. For  
example, to set multiple source download locations, multiple  
"master_sites" must be defined. Unless the second column items are  
few and short you should use multiple lines, separate lines with a  
backslash, and (to emphasize the unity of the block) indent the first  
line at a deeper level than the following lines as shown in this  
example.

destroot.keepdirs   ${destroot}${prefix}/var/run \
                     ${destroot}${prefix}/var/log \
                     ${destroot}${prefix}/var/cache/mrtg

The part I don't understand is "indent the first line at a deeper  
level than the following lines". What's meant by that? The left  
column of the first line in the example is not indented at all; it's  
at the very left of the document. And every line in the right column  
is aligned with every other line; the first line is not indented more  
or less than the others. The example shown is what's found in most  
Portfiles and is what we want to recommend, but that part of the  
description does not describe the example.