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##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
vmware_guest_disk should propose `disk_mode` parameter (like vmware_guest module).
The playbook bellow does not raise an error but disk is always added in `persistent` mode, even I set `independent_persistent` for `disk_mode` var.
If it's a bug please could you fix it? If it's not consider it as a feature request :)

##### ISSUE TYPE
- Feature Idea (or maybe a bug)

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

##### ADDITIONAL INFORMATION
<!--- 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
---
- name: get vm {{ target | upper }} facts
  vmware_guest_facts:
    hostname: "{{ vcenter_hostname }}"
    username: "{{ vcenter_username }}"
    password: "{{ vcenter_password }}"
    datacenter: "{{ datacenter }}"
    validate_certs: no
    name: "{{ target | upper }}"
  register: vm_facts
  delegate_to: localhost

- name: add disk to vm {{ target | upper }}
  vmware_guest_disk:
    hostname: "{{ vcenter_hostname }}"
    username: "{{ vcenter_username }}"
    password: "{{ vcenter_password }}"
    datacenter: "{{ datacenter }}"
    validate_certs: no
    name: "{{ target | upper }}"
    disk:
      - size_gb: "{{ size_gb }}"
        type: "{{ type }}"
        disk_mode: "{{ disk_mode }}"
        scsi_controller: "{{ scsi_controller }}" 
        unit_number: "{{ unit_number }}"
        datastore: "{{ vm_facts.instance.hw_datastores | first }}"
  delegate_to: localhost
```

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

- '   If C(size) specified then unit must be specified. There is no space allowed in between size number and unit.'
     - '   Only first occurrence in disk element will be considered, even if there are multiple size* parameters available.'
     - ' - C(type) (string): Valid values are:'
     - '     - C(thin) thin disk'
     - '     - C(eagerzeroedthick) eagerzeroedthick disk'
     - '     - C(thick) thick disk'
     - '     Default: C(thick) thick disk, no eagerzero.'
     - ' - C(datastore) (string): Name of datastore or datastore cluster to be used for the disk.'
     - ' - C(autoselect_datastore) (bool): Select the less used datastore. Specify only if C(datastore) is not specified.'
     - ' - C(scsi_controller) (integer): SCSI controller number. Valid value range from 0 to 3.'
     - '   Only 4 SCSI controllers are allowed per VM.'
     - '   Care should be taken while specifying C(scsi_controller) is 0 and C(unit_number) as 0 as this disk may contain OS.'
     - ' - C(unit_number) (integer): Disk Unit Number. Valid value range from 0 to 15. Only 15 disks are allowed per SCSI Controller.'
     - ' - C(scsi_type) (string): Type of SCSI controller. This value is required only for the first occurance of SCSI Controller.'
     - '   This value is ignored, if SCSI Controller is already present or C(state) is C(absent).'
     - '   Valid values are C(buslogic), C(lsilogic), C(lsilogicsas) and C(paravirtual).'
     - '   C(paravirtual) is default value for this parameter.'
     - ' - C(state) (string): State of disk. This is either "absent" or "present".'
     - '   If C(state) is set to C(absent), disk will be removed permanently from virtual machine configuration and from VMware storage.'
     - '   If C(state) is set to C(present), disk will be added if not present at given SCSI Controller and Unit Number.'
     - '   If C(state) is set to C(present) and disk exists with different size, disk size is increased.'
     - '   Reducing disk size is not allowed.'
     default: []
     type: list
extends_documentation_fragment: vmware.documentation
'''
EXAMPLES = '''
- name: Add disks to virtual machine using UUID
  vmware_guest_disk:
    hostname: "{{ vcenter_hostname }}"