old_contents: # Licensed to the StackStorm, Inc ('StackStorm') under one or more
  # contributor license agreements.  See the NOTICE file distributed with
  # this work for additional information regarding copyright ownership.
  # The ASF licenses this file to You under the Apache License, Version 2.0
  # (the "License"); you may not use this file except in compliance with
  # the License.  You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  __all__ = [
      'PACK_VIRTUALENV_DOESNT_EXIST',
      'PACK_VIRTUALENV_USES_PYTHON3'
  ]
  
  PACK_VIRTUALENV_DOESNT_EXIST = '''
  The virtual environment (%(virtualenv_path)s) for pack "%(pack)s" does not exist. Normally this is
  created when you install a pack using "st2 pack install". If you installed your pack by some other
  means, you can create a new virtual environment using the command:
  "st2 run packs.setup_virtualenv packs=%(pack)s"
  '''
  
  PACK_VIRTUALENV_USES_PYTHON3 = '''
  Virtual environment (%(virtualenv_path)s) for pack "%(pack)s" is using python3.
  Using Python 3 virtual environments in mixed deployments is only supported for Python runner
  actions and not sensors. If you want to run this sensor, please re-recreate the
  virtualenv environment with python2 binary.
  '''
  
new_contents: # Licensed to the StackStorm, Inc ('StackStorm') under one or more
  # contributor license agreements.  See the NOTICE file distributed with
  # this work for additional information regarding copyright ownership.
  # The ASF licenses this file to You under the Apache License, Version 2.0
  # (the "License"); you may not use this file except in compliance with
  # the License.  You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  __all__ = [
      'PACK_VIRTUALENV_DOESNT_EXIST',
      'PACK_VIRTUALENV_USES_PYTHON3'
  ]
  
  PACK_VIRTUALENV_DOESNT_EXIST = '''
  The virtual environment (%(virtualenv_path)s) for pack "%(pack)s" does not exist. Normally this is
  created when you install a pack using "st2 pack install". If you installed your pack by some other
  means, you can create a new virtual environment using the command:
  "st2 run packs.setup_virtualenv packs=%(pack)s"
  '''
  
  PACK_VIRTUALENV_USES_PYTHON3 = '''
  Virtual environment (%(virtualenv_path)s) for pack "%(pack)s" is using Python 3.
  Using Python 3 virtual environments in mixed deployments is only supported for Python runner
  actions and not sensors. If you want to run this sensor, please re-recreate the
  virtual environment with python2 binary:
  "st2 run packs.setup_virtualenv packs=%(pack)s python3=false"
  '''
  
subject: Update error message.