human
Complete the below
def create_bootstrap_script(extra_text, python_version=''):

    ''''Creates a bootstrap script, which is like this script but with
    extend_parser, adjust_options, and after_install hooks.
    This returns a string that (written to disk of course) can be used
    as a bootstrap script with your own customizations.  The script
    will be the standard virtualenv.py script, with your extra text
    added (your extra text should be Python program).
    If you include these functions, they will be called:
    ``extend_parser(optparse_parser)``:
    You can add or remove options from the parser here.
    ``adjust_options(options, args)``:
    You can change options here, or change the args (if you accept
    different kinds of arguments, be sure you modify ``args`` so it is
    only ``[DEST_DIR]``).
    ``after_install(options, home_dir)``:
    After everything is installed, this function is called.  This
    is probably the function you are most likely to use.  An
    example would be::
    def after_install(options, home_dir):
    subprocess.call([join(home_dir, \'bin\', \'easy_install\'),
    \'MyPackage\'])
    subprocess.call([join(home_dir, \'bin\', \'my-package-script\'),
    \'setup\', home_dir])
    This example immediately installs a package, and runs a setup
    script from that package.
    If you provide something like ``python_version=\'2.5\'`` then the
    script will start with ``#!/usr/bin/env python2.5`` instead of
    ``#!/usr/bin/env python``.  You can use this when the script must
    be run with a particular Python version.'
    '''
 Can you provide a the Python program you requested?
assistant
#Here is the Python program you requested.
    filename = __file__
    if filename.endswith('.pyc'):
        filename = filename[:(-1)]
    with codecs.open(filename, 'r', encoding='utf-8') as f:
        content = f.read()
    py_exe = ('python%s' % python_version)
    content = ((('#!/usr/bin/env    %s\n' % py_exe) + '##    WARNING:    This    file    is    generated\n') + content)
    return content.replace('##EXTEND##', extra_text)