class_docstr: Dictionary that maps the name of the buffers to the
  :class:`~prompt_toolkit.buffer.Buffer` instances.
  
  This mapping also keeps track of which buffer currently has the focus.
  (Some methods receive a 'cli' parameter. This is useful for applications
  where this `BufferMapping` is shared between several applications.)
docstr: Focus the buffer with the given name.
docstr_tok: ["Focus","the","buffer","with","the","given","name","."]
code: def focus(self, cli, buffer_name):
      """
      Focus the buffer with the given name.
      """
      assert isinstance(buffer_name, six.text_type)
      self.focus_stack = [buffer_name]
  
file_path: catboost/contrib/python/prompt-toolkit/py2/prompt_toolkit/buffer_mapping.py
imports: from __future__ import unicode_literals
  from .enums import DEFAULT_BUFFER, SEARCH_BUFFER, SYSTEM_BUFFER, DUMMY_BUFFER
  from .buffer import Buffer, AcceptAction
  from .history import InMemoryHistory
  import six
label_desc: Use image node_id 5 for calling the BufferMapping obj's underlying member method code with example usage: obj.focus(cli, buffer_name) without return types