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##### SUMMARY
<!--- Explain the problem briefly below -->
Ansible currently contains two modules for managing AWS EC2 instances: [`ec2`](https://docs.ansible.com/ansible/latest/modules/ec2_module.html) and [`ec2_instance`](https://docs.ansible.com/ansible/latest/modules/ec2_instance_module.html).

There is considerable overlap between the modules, but it's unclear what the differences are and why there are two modules in the first place.

##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ec2
ec2_instance

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.10.0.dev0
  config file = /home/user/.ansible.cfg
  configured module search path = ['/home/user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/user/ansible/lib/ansible
  executable location = /home/user/ansible/bin/ansible
  python version = 3.7.5 (default, Oct 27 2019, 15:43:29) [GCC 9.2.1 20191022]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
RETRY_FILES_ENABLED(/home/user/.ansible.cfg) = False
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Debian bullseye/sid

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

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

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
N/A

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
N/A
```

if isinstance(group_name, string_types):
                group_name = [group_name]
            unmatched = set(group_name).difference(str(grp.name) for grp in grp_details)
            if len(unmatched) > 0:
                module.fail_json(msg="The following group names are not valid: %s" % ', '.join(unmatched))
            group_id = [str(grp.id) for grp in grp_details if str(grp.name) in group_name]
        
        elif group_id:
            
            if isinstance(group_id, string_types):
                group_id = [group_id]
            grp_details = ec2.get_all_security_groups(group_ids=group_id)
            group_name = [grp_item.name for grp_item in grp_details]
    except boto.exception.NoAuthHandlerFound as e:
        module.fail_json(msg=str(e))
    
    running_instances = []
    count_remaining = int(count)
    if id is not None:
        filter_dict = {'client-token': id, 'instance-state-name': 'running'}
        previous_reservations = ec2.get_all_instances(None, filter_dict)
        for res in previous_reservations:
            for prev_instance in res.instances:
                running_instances.append(prev_instance)
        count_remaining = count_remaining - len(running_instances)
    
    if count_remaining == 0:
        changed = False
    else:
        changed = True