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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _remove_double_brackets(text):
 """Remove double brackets, but leave the viewable text. Args: text: a string Returns: a string """


  def replacement_fn(s):
    if ":" in s:
      # this is probably a category or something like that.
      return ""
    # keep the part after the bar.
    bar_pos = s.find("|")
    if bar_pos == -1:
      return s
    return s[bar_pos + 1:]

  return _find_and_replace(text, "[[", "]]", replacement_fn)