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 mkdir_and_copy_file(self, header):
    install_dir = os.path.join(self.install_dir, os.path.dirname(header))
    # Get rid of some extra intervening directories so we can have fewer
    # directories for -I
    install_dir = re.sub('/google/protobuf_archive/src', '', install_dir)

    # Copy eigen code into tensorflow/include.
    # A symlink would do, but the wheel file that gets created ignores
    # symlink within the directory hierarchy.
    # NOTE(keveman): Figure out how to customize bdist_wheel package so
    # we can do the symlink.
    if 'external/eigen_archive/' in install_dir:
      extra_dir = install_dir.replace('external/eigen_archive', '')
      if not os.path.exists(extra_dir):
        self.mkpath(extra_dir)
      self.copy_file(header, extra_dir)

    if not os.path.exists(install_dir):
      self.mkpath(install_dir)
    return self.copy_file(header, install_dir)