"key already in storage" should be a warning, not a fatal, and should not stop execution of the task

[sneak]

sneak@rabotnik:~$ steempy importaccount REDACTED --roles owner active posting memo
Account Passphrase: 
Importing owner key!
Passphrase: 
Importing active key!
Traceback (most recent call last):
  File "/Users/sneak/Library/Homebrew/bin/steempy", line 4, in <module>
    __import__('pkg_resources').run_script('steem==0.18.9', 'steempy')
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/pkg_resources/__init__.py", line 739, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1501, in run_script
    exec(script_code, namespace, namespace)
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/steem-0.18.9-py3.6.egg/EGG-INFO/scripts/steempy", line 7, in <module>
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/steem-0.18.9-py3.6.egg/steem/cli.py", line 1334, in legacy
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/steem-0.18.9-py3.6.egg/steem/wallet.py", line 212, in addPrivateKey
  File "/Users/sneak/Library/Homebrew/lib/python3.6/site-packages/steem-0.18.9-py3.6.egg/steembase/storage.py", line 192, in add
ValueError: Key already in storage
sneak@rabotnik:~$