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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 'snapshot' not in volume and 'ephemeral' not in volume:
        if 'volume_size' not in volume:
            module.fail_json(msg='Size must be specified when creating a new volume or modifying the root volume')
    if 'snapshot' in volume:
        if volume_type == 'io1' and 'iops' not in volume:
            module.fail_json(msg='io1 volumes must have an iops value set')
        if 'iops' in volume:
            snapshot = ec2.get_all_snapshots(snapshot_ids=[volume['snapshot']])[0]
            size = volume.get('volume_size', snapshot.volume_size)
            if int(volume['iops']) > MAX_IOPS_TO_SIZE_RATIO * size:
                module.fail_json(msg='IOPS must be at most %d times greater than size' % MAX_IOPS_TO_SIZE_RATIO)
    if 'ephemeral' in volume:
        if 'snapshot' in volume:
            module.fail_json(msg='Cannot set both ephemeral and snapshot')
    if boto_supports_volume_encryption():
        return BlockDeviceType(snapshot_id=volume.get('snapshot'),
                               ephemeral_name=volume.get('ephemeral'),
                               size=volume.get('volume_size'),
                               volume_type=volume_type,
                               delete_on_termination=volume.get('delete_on_termination', False),
                               iops=volume.get('iops'),
                               encrypted=volume.get('encrypted', None))
    else:
        return BlockDeviceType(snapshot_id=volume.get('snapshot'),
                               ephemeral_name=volume.get('ephemeral'),
                               size=volume.get('volume_size'),
                               volume_type=volume_type,
                               delete_on_termination=volume.get('delete_on_termination', False),
                               iops=volume.get('iops'))
def boto_supports_param_in_spot_request(ec2, param):