关于python：错误：’elasticsearch’后端需要安装’requests’。我如何解决它？

Error: The 'elasticsearch' backend requires the installation of 'requests'. How do I fix it?

当我在haystack和elasticsearch支持的应用程序中运行"python manage.py rebuild_index"时，我遇到了问题。

Python 2.7
Django版本1.6.2
干草堆2.1.0
Elasticsearch 1.0

请查看出现的错误：

Traceback (most recent call last):
File"manage.py", line 10, in
execute_from_command_line(sys.argv)
File"/usr/lib/python2.7/site-packages/django/core/management/init.py", line 399, in > execute_from_command_line
utility.execute()
File"/usr/lib/python2.7/site-packages/django/core/management/init.py", line 392, in > execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File"/usr/lib/python2.7/site-packages/django/core/management/base.py", line 242, in >run_from_argv
self.execute(*args, **options.dict)
File"/usr/lib/python2.7/site-packages/django/core/management/base.py", line 285, in execute
output = self.handle(*args, **options)
File"/usr/lib/python2.7/site-packages/haystack/management/commands/rebuild_index.py", line 15, in handle
call_command('clear_index', **options)
File"/usr/lib/python2.7/site-packages/django/core/management/init.py", line 159, in call_command
return klass.execute(*args, **defaults)
File"/usr/lib/python2.7/site-packages/django/core/management/base.py", line 285, in execute
output = self.handle(*args, **options)
File"/usr/lib/python2.7/site-packages/haystack/management/commands/clear_index.py", line 48, in handle
backend = connections[backend_name].get_backend()
File"/usr/lib/python2.7/site-packages/haystack/utils/loading.py", line 98, in getitem
self._connections[key] = load_backend(self.connections_info[key]['ENGINE'])(using=key)
File"/usr/lib/python2.7/site-packages/haystack/utils/loading.py", line 51, in load_backend
return import_class(full_backend_path)
File"/usr/lib/python2.7/site-packages/haystack/utils/loading.py", line 18, in import_class
module_itself = importlib.import_module(module_path)
File"/usr/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
import(name)
File"/usr/lib/python2.7/site-packages/haystack/backends/elasticsearch_backend.py", line 21, in
raise MissingDependency("The 'elasticsearch' backend requires the installation of 'requests'.")
haystack.exceptions.MissingDependency: The 'elasticsearch' backend requires the installation of 'requests'.

我已经安装了运行这些应用程序所需的所有软件包，但询问请求是什么，它是什么？