def install_pip(self, package, save=True, save_dev=False):
        """Installs a pip package.

        :param save: if `True`, pins the package to the Hydrogen requirements
            YAML file.
        :param save_dev: if `True`, pins the package as a development
            dependency to the Hydrogen requirements YAML file.
        :param return: a **single** :class:`Requirement` object, representing
            the installed version of the given package.
        """
        requirement = Requirement.coerce(package)
        click.echo("pip install " + requirement.package)
        cmd = envoy.run("pip install {}".format(str(requirement)))
        if cmd.status_code == 0:
            installed_packages = get_installed_pypackages()
            package = installed_packages[requirement.package]
            requirement.version = "=={}".format(package.version)
            if save:
                self.requirements["all"].add(requirement)
            if save_dev:
                self.requirements["dev"].add(requirement)
            if save or save_dev:
                self.requirements.save()
            return requirement
        else:
            fatal(cmd.std_err)
def delete(self, dn, controls=None):

        self.result = { 'dn' : '',
                        'referrals' : None,
                        'description' : 'success',
                        'result' : 0,
                        'message' : '',
                        'type' : 'addResponse'}

        # Check to see if the user exists in the directory
        try:
            index = self._find_user(dn)
        except StopIteration:
            # If we get here the user doesn't exist so continue
            self.result["description"] = "failure"
            self.result["result"] = 32
            self.result["message"] = "Error no such object: {0}".format(dn)
            return False

        # Delete the entry object for the user
        self.directory.pop(index)

        # Attempt to write changes to disk
        with open(DIRECTORY, 'w+') as f:
            f.write(str(self.directory))

        return True