Hello,
You have to define one char field to save a binary file.
In your case :

Py File:
file1 = fields.Binary("Upload file1")
file1_name = fields.Char('File Name1')
file2 = fields.Binary("Upload file2")
file2_name = fields.Char('File Name2')

XML File :
<field name="file1" filename="file1_name"/>
<field name="file1_name" invisible="1"/>
<field name="file2" filename="file2_name"/>
<field name="file2_name" invisible="1"/>

Hope it will works for you.
Thanks.