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 test_impl(nsyms):
            max_num_days = 100
            all_res = 0.0
            for i in sdc.prange(nsyms):
                s_open = 20 * np.ones(max_num_days)
                s_low = 28 * np.ones(max_num_days)
                s_close = 19 * np.ones(max_num_days)
                df = pd.DataFrame({'Open': s_open, 'Low': s_low, 'Close': s_close})
                df['Stdev'] = df['Close'].rolling(window=90).std()
                df['Moving Average'] = df['Close'].rolling(window=20).mean()
                df['Criteria1'] = (df['Open'] - df['Low'].shift(1)) < -df['Stdev']
                df['Criteria2'] = df['Open'] > df['Moving Average']
                df['BUY'] = df['Criteria1'] & df['Criteria2']
                df['Pct Change'] = (df['Close'] - df['Open']) / df['Open']
                df['Rets'] = df['Pct Change'][df['BUY']]
                all_res += df['Rets'].mean()
            return all_res