class_docstr: Completer which can be used for autocompletion according to variables in
  the grammar. Each variable can have a different autocompleter.
  
  :param compiled_grammar: `GrammarCompleter` instance.
  :param completers: `dict` mapping variable names of the grammar to the
                     `Completer` instances to be used for each variable.
docstr: Remove duplicates, while keeping the order.
  (Sometimes we have duplicates, because the there several matches of the
  same grammar, each yielding similar completions.)
code: def _remove_duplicates(self, items):
      """
      Remove duplicates, while keeping the order.
      (Sometimes we have duplicates, because the there several matches of the
      same grammar, each yielding similar completions.)
      """
      result = []
      for i in items:
          if i not in result:
              result.append(i)
      return result
  
file_path: catboost/contrib/python/prompt-toolkit/py2/prompt_toolkit/contrib/regular_languages/completion.py
imports: from __future__ import unicode_literals
  from prompt_toolkit.completion import Completer, Completion
  from prompt_toolkit.document import Document
  from .compiler import _CompiledGrammar
label_desc: Use image node_id 4 for calling the GrammarCompleter obj's underlying member method code with example usage: obj._remove_duplicates(items) and returns: result