[web2py] Using MARKMIN helper causes HELPER.elements() function to produce wrong output

[Liam]

Unless this is expected behaviour...

In the example below, I expected one DIV, one SPAN and maybe one P when 
using the .elements() function. However, the MARKMIN input always gets 
included as a raw string, even when passing 'span' as an argument.
>>> test = DIV(MARKMIN('**a**'), SPAN('b'))
>>> test.elements()
[<gluon.html.DIV at 0x33a3390>, '**a**', <gluon.html.SPAN at 0x33a3350>]
>>> test.elements('span')
['**a**', <gluon.html.SPAN at 0x33a3350>]
>>> test.element('span')
'**a**'