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 patch(self):
        """Adjust OpenFOAM build for spack.
           Where needed, apply filter as an alternative to normal patching."""
        self.rename_source()
        add_extra_files(self, self.common, self.assets)

        # Avoid WM_PROJECT_INST_DIR for ThirdParty, site or jobControl.
        # Use openfoam-site.patch to handle jobControl, site.
        #
        # Filtering: bashrc,cshrc (using a patch is less flexible)
        edits = {
            'WM_THIRD_PARTY_DIR':
            r'$WM_PROJECT_DIR/ThirdParty #SPACK: No separate third-party',
            'WM_VERSION': str(self.version),  # consistency
            'FOAMY_HEX_MESH': '',  # This is horrible (unset variable?)
        }
        rewrite_environ_files(  # Adjust etc/bashrc and etc/cshrc
            edits,
            posix=join_path('etc', 'bashrc'),
            cshell=join_path('etc', 'cshrc'))