[Q] sub-methods ?

[Arsenal]

Hello all,

I am new to python. I am reading a chapter on wxPython, it has the
following example.

===========
wc = wxLayoutConstraints()
wc.height.AsIs()
wc.left.SameAs(someButton, wxLeft)
wc.width.PercentOf(parentPanel, 50)
myButton.SetConstraints(wc)
===========

I am puzzled by the these. 

wc is an object instance.

Aren't "height", "left", "width" themselves methods? Why it seems
there are some "sub-methods" like AsIs(), SameAs() behind it?

I am sure i have got something wrong, would anyone pls enlighten me 
:) ?

Thanks!