'Install everything in this set (after having downloaded and unpacked the packages)'

def install(self, install_options, global_options=(), *args, **kwargs):

    to_install = [r for r in self.requirements.values() if (not r.satisfied_by)]
    distribute_req = pkg_resources.Requirement.parse('distribute>=0.7')
    for req in to_install:
        if ((req.name == 'distribute') and (req.installed_version in distribute_req)):
            to_install.remove(req)
            to_install.append(req)
    if to_install:
        logger.notify(('Installing    collected    packages:    %s' % ',    '.join([req.name for req in to_install])))
    logger.indent += 2
    try:
        for requirement in to_install:
            if (requirement.name == 'setuptools'):
                try:
                    distribute_requirement = pkg_resources.Requirement.parse('distribute<0.7')
                    existing_distribute = pkg_resources.get_distribution('distribute')
                    if (existing_distribute in distribute_requirement):
                        requirement.conflicts_with = existing_distribute
                except pkg_resources.DistributionNotFound:
                    pass
            if requirement.conflicts_with:
                logger.notify(('Found    existing    installation:    %s' % requirement.conflicts_with))
                logger.indent += 2
                try:
                    requirement.uninstall(auto_confirm=True)
                finally:
                    logger.indent -= 2
            try:
                requirement.install(install_options, global_options, *args, **kwargs)
            except:
                if (requirement.conflicts_with and (not requirement.install_succeeded)):
                    requirement.rollback_uninstall()
                raise
            else:
                if (requirement.conflicts_with and requirement.install_succeeded):
                    requirement.commit_uninstall()
            requirement.remove_temporary_source()
    finally:
        logger.indent -= 2
    self.successfully_installed = to_install
