is None, the next row read is used as the fieldnames. In the common case,
this means the programmer doesn't need to know the fieldnames ahead of time.
The first row of the file will be used. In the uncommon case, this means
the programmer can set the reader's fieldnames attribute to None at any time
and have the next row read as the next set of fieldnames, so a csv file can
contain several "sections", each with different fieldnames.
and test_support.run_classtests() into run_unittest()
and use it wherever possible.
Also don't use "from test.test_support import ...", but
"from test import test_support" in a few spots.
From SF patch #662807.
Skip Montanaro
Walter Dörwald
Tim Peters
Guido van Rossum