from gi.repository import Gtk

def add_column(treeview, label, index, xalign=None, col_fg=None, col_bg=None, visible=True):
    col = Gtk.TreeViewColumn(label)
    cell = Gtk.CellRendererText()
    col.pack_start(cell, True)
    col.add_attribute(cell, 'text', index)
    if xalign:
        cell.set_property('xalign', xalign)
    if col_fg:
        col.add_attribute(cell, 'foreground', col_fg)
    if col_bg:
        col.add_attribute(cell, 'background', col_bg)
    treeview.append_column(col)

def get_value(treeview, column=0):
    """
    Returns the value of the specified column of the linked model
    """
    try:
        selection = treeview.get_selection()
    except:
        return None
    if selection.get_mode() == Gtk.SelectionMode.SINGLE:
        (model, iter) = selection.get_selected()
        if iter:
            return model.get_value(iter, column)
    return None

def set_value(treeview, column, value):
    """
    Sets the value of the specified column of the linked model
    """
    try:
        selection = treeview.get_selection()
    except:
        return False
    if selection.get_mode() == Gtk.SelectionMode.SINGLE:
        (model, iter) = selection.get_selected()
        model.set_value(iter, column, value)
        return True
    else:
        return False