Data not flushed at the moment

[MindClass]

I've to modifying a file, then I use a method imported that access to
that file and has to read the new data, but they are not read ( as if
the data were not flushed at the moment even using .close()
explicitly).

---------------------------------------
    ...
    ...
    # If it is not installed, it looking for the line and insert it.
    if not is_application:
        print "Activating I18n application ..."
        writefile_line = 0
        a = fileinput.input(settings, inplace=1)
#        for line in fileinput.input(settings, inplace=1):
        for line in a:
            writefile_line += 1
            if writefile_line == readfile_line:
                print "    '%s'," % application_name
                print line[:-1]
            else:
                print line[:-1]
        a.close()

        update()

def update():
    # Update the data base.
    try:
        from django.core.management import syncdb
    except ImportError, err:
        print "Can't import from Django: %s" % err
        sys.exit(1)

    syncdb()
---------------------------------------

Note that it only fails if the update() method is run inner of 'if not
is_application', and I don't understand because it is happening so. But
the problem is that I need run it when that condition is performed. Any
idea?