old_contents: #!/usr/bin/env python
  #
  # Licensed to the Apache Software Foundation (ASF) 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.
  #
  
  
  from pulsar import Function
  
  # Function that appends something to incoming input based on config supplied
  class ConfigBasedAppendFunction(Function):
    def __init__(self):
      pass
  
    def process(self, input, context):
      key = "config-key"
      append_value = "!"
      if key in context.get_user_config_map():
        append_value = context.get_user_config_value(key)
      return input + append_value
  
new_contents: #!/usr/bin/env python
  #
  # Licensed to the Apache Software Foundation (ASF) 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.
  #
  
  
  from pulsar import Function
  
  # Function that appends something to incoming input based on config supplied
  class ConfigBasedAppendFunction(Function):
    def __init__(self):
      pass
  
    def process(self, input, context):
      key = "config-key"
      append_value = "!"
      if key in context.get_user_config_map():
        append_value = context.get_user_config_value(key)
      return input + str(append_value)
  
subject: Make sure that the returned object is string for conversion purposes (#2946)