def add_context(context, new_input):
    """
    Update the context strings for all speakers in a conversation.
    Args:
      context:  A dictionary of context strings for all speakers
      new_input: A string to be appended to the context for all speakers.
    Returns:
      new_context: An updated dictionary of context strings for all speakers.
    """
    new_context = {}
    for speaker in context.keys():
        new_context[speaker] = context[speaker] + new_input
    return new_context