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##### SUMMARY
@LKaemmerling As discussed in https://github.com/ansible/ansible/issues/59133#issuecomment-515133800, you said there would be network filtering in the hcloud dynamic inventory plugin (https://docs.ansible.com/ansible/latest/plugins/inventory/hcloud.html) in Ansible 2.9. But this functionality still doesn't appear. Could it be added? There are many cases where you only want to run ansible commands against servers in some networks only.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
hcloud dynamic inventory


<!--- Describe how the feature would be used, why it is needed and what it would solve -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can also paste gist.github.com links for larger files -->

plugin: hcloud
# Example with locations, types, groups and token
plugin: hcloud
token: foobar
locations:
  - nbg1
types:
  - cx11
# Group by a location with prefix e.g. "hcloud_location_nbg1"
# and image_os_flavor without prefix and separator e.g. "ubuntu"
# and status with prefix e.g. "server_status_running"
plugin: hcloud
keyed_groups:
  - key: location
    prefix: hcloud_location
  - key: image_os_flavor
    separator: ""
  - key: status
    prefix: server_status
"""
import os
from ansible.errors import AnsibleError
from ansible.module_utils._text import to_native
from ansible.plugins.inventory import BaseInventoryPlugin, Constructable
from ansible.release import __version__
try:
    from hcloud import hcloud
except ImportError:
    raise AnsibleError("The Hetzner Cloud dynamic inventory plugin requires hcloud-python.")
class InventoryModule(BaseInventoryPlugin, Constructable):