>>> import albatross
>>> ctx = albatross.SimpleContext('.')
>>> ctx.locals.a = 30
>>> albatross.Template(ctx, '<magic>', '''
... <al-if expr="a < 15">
...  a (<al-value expr="a">) is less than 15.
... <al-elif expr="a < 25">
...  a (<al-value expr="a">) is greater than or equal to 15 and less than 25.
... <al-elif expr="a < 35">
...  a (<al-value expr="a">) is greater than or equal to 25 and less than 35.
... <al-else>
...  a (<al-value expr="a">) is greater than or equal to 25.
... </al-if>
... ''').to_html(ctx)
>>> ctx.flush_content()
a (30) is greater than or equal to 25 and less than 35.