[ADE] Failed to enable the extension with error: No module named parted,

Hi, I'm unable to intialize ADE for linux machine (Ubuntu 18.04). Any ideas how to solve it?

`PS /home/> az vm encryption enable --disk-encryption-keyvault {kv_name} --name {vm_name} --resource-group {rg_name} --volume-type ALL
`
Exception:

> Deployment failed. Correlation ID: b65ca250-bf9d-4c72-8456-08ec64c8efbd. VM has reported a failure when processing extension 'AzureDiskEncryptionForLinux'.
> Error message: "Failed to enable the extension with error: No module named parted, stack trace: Traceback (most recent call last):
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/handle.py", line 2209, in daemon
> daemon_encrypt()
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/handle.py", line 1940, in daemon_encrypt
> from oscrypto.ubuntu_1604 import Ubuntu1604EncryptionStateMachine
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/oscrypto/ubuntu_1604/__init__.py", line 16, in
> from .Ubuntu1604EncryptionStateMachine import *
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/oscrypto/ubuntu_1604/Ubuntu1604EncryptionStateMachine.py", line 37, in
> from .encryptstates import *
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/oscrypto/ubuntu_1604/encryptstates/__init__.py", line 33, in
> from .SplitRootPartitionState import *
> File "/var/lib/waagent/Microsoft.Azure.Security.AzureDiskEncryptionForLinux-1.2.0.72/main/oscrypto/ubuntu_1604/encryptstates/SplitRootPartitionState.py", line 26, in
> import parted
> ImportError: No module named parted
> "

Start by reproducing the shown `az vm encryption enable` command on Ubuntu 18.04 and inspect the extension traceback. Read `main/handle.py`, `oscrypto/ubuntu_1604/Ubuntu1604EncryptionStateMachine.py`, and `oscrypto/ubuntu_1604/encryptstates/SplitRootPartitionState.py` around the `parted` import; done means ADE enables without the missing-module failure.

Written by the indexing model from the issue text.