Pyform dynamic styling does not take an effect

Question

I started pyforms yesterday and it looks like many parts of the framework is not documented yet.

I write an application which requires a style change on demand. I insist on using ControlButton.style and not a CSS file. The documentation does not provide how to use style property and my try failed. It does not make any effect.

from pyforms.basewidget import BaseWidget
from pyforms.controls import ControlText
from pyforms.controls import ControlButton
import os


class GUI(BaseWidget):

    def __init__(self, *args, **kwargs):
        super().__init__('A test')

        self.set_margin(10)

        self._directory = ControlText('Directory')
        self._directory.value = 'C:\\'
        self._directory.changed_event = self.referesh_check
        self._ok  = ControlButton('OK')
        self._formset = [ ('_directory', ' ', '_ok') ]
        self.referesh_check()

    def referesh_check(self):
        dirpath = self._directory.value
        if os.path.exists(dirpath):
            print('found: ', dirpath)
            self._directory.style='color:green'
        else:
            print('not found: ', dirpath)
            self._directory.style='color:red'
            pass

if __name__ == '__main__':
    from pyforms import start_app
    start_app(GUI)

---

Note:

Using style as method fails with an error

self._directory.style('background-color:green')

AttributeError: 'ControlText' object has no attribute 'style'