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 _format_unhandled_exception_log(cls, exc, tb, add_newline, should_print_backtrace):
        exc_type = type(exc)
        exception_full_name = "{}.{}".format(exc_type.__module__, exc_type.__name__)
        exception_message = str(exc) if exc else "(no message)"
        maybe_newline = "\n" if add_newline else ""
        return cls._UNHANDLED_EXCEPTION_LOG_FORMAT.format(
            exception_type=exception_full_name,
            backtrace=cls._format_traceback(
                traceback_lines=traceback.format_tb(tb),
                should_print_backtrace=should_print_backtrace,
            ),
            exception_message=exception_message,
            maybe_newline=maybe_newline,
        )