A recursive update - useful for merging config files.
>>> a = '''[section1]
... option1 = True
... [[subsection]]
... more_options = False
... # end of file'''.splitlines()
>>> b = '''# File is user.ini
... [section1]
... option1 = False
... # end of file'''.splitlines()
>>> c1 = ConfigObj(b)
>>> c2 = ConfigObj(a)
>>> c2.merge(c1)
>>> c2
ConfigObj({'section1': {'option1': 'False', 'subsection': {'more_options': 'False'}}})