GTK-Python树视图排序列数据（文件大小-字节数据）

我有一个带有Python代码的GTK GUI。GUI上有一个树视图。我需要在树视图上列出文件大小，并通过单击列按文件大小排序。但它使用大小作为字符串对文件进行排序

排序此文件的

常用方法是什么

使用字符串文件大小值（带有单元格函数或自定义排序函数）
使用整型文件大小值（带有单元格函数或自定义排序函数）
另一种方式
以下是简化代码：

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

builder = Gtk.Builder()
builder.add_from_file('test1.glade')
window1 = builder.get_object('window1')
treeview1 = builder.get_object('treeview1')

class Signals:
    def on_window1_destroy(self, widget):
        Gtk.main_quit()

file_data = [["file1", 12345],
             ["file2", 1234567890],
             ["file3", 1234567],
             ["file4", 1234]]

# Some code to convert data
# .
# .
# .

file_data_converted = [["file1", "12.3 KB"],
                       ["file2", "1.23 GB"],
                       ["file3", "1.23 MB "],
                       ["file4", "1.23 KB"]]

treestore1 = Gtk.TreeStore(str, str)
piter1 = treestore1.append(None, file_data_converted[0])
piter2 = treestore1.append(None, file_data_converted[1])
piter3 = treestore1.append(None, file_data_converted[2])
piter4 = treestore1.append(None, file_data_converted[3])

treeview1.set_model(treestore1)

for i, column_title in enumerate(["File", "Size"]):
    renderer = Gtk.CellRendererText()
    column = Gtk.TreeViewColumn(column_title, renderer, text=i)
    column.set_sort_column_id(i)
    treeview1.append_column(column)

builder.connect_signals(Signals())
window1.show_all()
Gtk.main()

这是Glade文件：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.22.1 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkWindow" id="window1">
    <property name="can_focus">False</property>
    <property name="default_width">300</property>
    <property name="default_height">300</property>
    <child>
      <placeholder/>
    </child>
    <child>
      <object class="GtkTreeView" id="treeview1">
        <property name="visible">True</property>
        <property name="can_focus">True</property>
        <child internal-child="selection">
          <object class="GtkTreeSelection"/>
        </child>
      </object>
    </child>
  </object>
</interface>


假的
300
300
真的
真的

软件信息：
python3.7，GTK3。
存储中需要有一个隐藏列，文件大小为整数，仅用于排序。下面是一个例子：

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

builder = Gtk.Builder()
builder.add_from_file('gtk.ui')
window1 = builder.get_object('window1')
treeview1 = builder.get_object('treeview1')

class Signals:
    def on_window1_destroy(self, widget):
        Gtk.main_quit()


file_data_converted = [["file1", 12345, "12.3 KB"],
                       ["file2", 1234567890, "1.23 GB"],
                       ["file3", 1234567, "1.23 MB "],
                       ["file4", 1234, "1.23 KB"]]

treestore1 = Gtk.TreeStore(str, int, str)
piter1 = treestore1.append(None, file_data_converted[0])
piter2 = treestore1.append(None, file_data_converted[1])
piter3 = treestore1.append(None, file_data_converted[2])
piter4 = treestore1.append(None, file_data_converted[3])

treeview1.set_model(treestore1)

# file name column
renderer = Gtk.CellRendererText()
column = Gtk.TreeViewColumn('File', renderer, text=0)
column.set_sort_column_id(0)
treeview1.append_column(column)
# file size column
renderer = Gtk.CellRendererText()
column = Gtk.TreeViewColumn('Size', renderer, text=2)
column.set_sort_column_id(1)
treeview1.append_column(column)

builder.connect_signals(Signals())
window1.show_all()
Gtk.main()