DATE: today

===== This is a test of HTML templates =====

Note: When using HTML templates, the DocOnce file cannot have a title
(to avoid generating a header). It should neither have an author.

======= This is a 7 heading =======

Here is some code:
!bc pycod
class Diff:
    def __init__(self, f, h=1E-5):
        self.f = f
        self.h = float(h)

class Forward1(Diff):
    def __call__(self, x):
        f, h = self.f, self.h
        return (f(x+h) - f(x))/h
!ec

===== This is a 5 heading =====

The template can be any HTML file with header and footer and
three possible slots: *title*, *date* and *main*,
where *main* will become the DocOnce file (the main body of text),
*title* is the first heading in the DocOnce file, and
*date* is extracted from the DocOnce file (if present).


