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 ldlq(bch):
    """creates the surface plots of a BCH reader object
    with a ld-lq identification"""
    beta = bch.ldq['beta']
    i1 = bch.ldq['i1']
    torque = bch.ldq['torque']
    ld = np.array(bch.ldq['ld'])
    lq = np.array(bch.ldq['lq'])
    psid = bch.ldq['psid']
    psiq = bch.ldq['psiq']

    rows = 3
    fig = plt.figure(figsize=(10, 4*rows))
    fig.suptitle('Ld-Lq Identification {}'.format(bch.filename), fontsize=16)
    fig.add_subplot(rows, 2, 1, projection='3d')
    i1beta_torque(i1, beta, torque)

    fig.add_subplot(rows, 2, 2, projection='3d')
    i1beta_psid(i1, beta, psid)

    fig.add_subplot(rows, 2, 3, projection='3d')
    i1beta_psiq(i1, beta, psiq)

    fig.add_subplot(rows, 2, 4, projection='3d')
    try:
        i1beta_psim(i1, beta, bch.ldq['psim'])
    except:
        i1beta_up(i1, beta, bch.ldq['up'])

    fig.add_subplot(rows, 2, 5, projection='3d')
    i1beta_ld(i1, beta, ld)

    fig.add_subplot(rows, 2, 6, projection='3d')
    i1beta_lq(i1, beta, lq)