class_docstr: Parser for VT100 input stream.
  
  Feed the data through the `feed` method and the correct callbacks of the
  `input_processor` will be called.
  
  ::
  
      def callback(key):
          pass
      i = InputStream(callback)
      i.feed('data...')
  
  :attr input_processor: :class:`~prompt_toolkit.key_binding.InputProcessor` instance.
docstr: Return the key that maps to this prefix.
docstr_tok: ["Return","the","key","that","maps","to","this","prefix","."]
code: def _get_match(self, prefix):
      """
      Return the key that maps to this prefix.
      """
      # (hard coded) If we match a CPR response, return Keys.CPRResponse.
      # (This one doesn't fit in the ANSI_SEQUENCES, because it contains
      # integer variables.)
      if _cpr_response_re.match(prefix):
          return Keys.CPRResponse
  
      elif _mouse_event_re.match(prefix):
          return Keys.Vt100MouseEvent
  
      # Otherwise, use the mappings.
      try:
          return ANSI_SEQUENCES[prefix]
      except KeyError:
          return None
  
imports: from __future__ import unicode_literals
  import os
  import re
  import six
  import termios
  import tty
  from six.moves import range
  from ..keys import Keys
  from ..key_binding.input_processor import KeyPress
label_desc: Use image node_id 4 for calling the InputStream obj's underlying member method code with example usage: obj._get_match(prefix) and returns: Keys, ANSI_SEQUENCES, Keys, None