new_contents: """
  FCS keyword strings
  """
  
  # FCS 3.1 reserves certain keywords as being part of the FCS standard. Some
  # of these are required, and others are optional. However, all of these
  # keywords shall be prefixed by the '$' character. No other keywords shall
  # begin with the '$' character. All keywords are case-insensitive, however
  # most cytometers use all uppercase for keyword strings. FlowKit follows
  # the convention used in FlowIO and internally stores and references all
  # FCS keywords as lowercase for more convenient typing by developers.
  #
  # NOTE: When creating new FCS files, some keywords (and values) are set
  #    automatically by the create_fcs function. The standard list of
  #    keywords will be ignored if included in the metadata passed to
  #    the create_fcs function.
  #
  # noinspection SpellCheckingInspection
  FCS_STANDARD_REQUIRED_KEYWORDS = [
      'beginanalysis',
      'begindata',
      'beginstext',
      'byteord',
      'datatype',
      'endanalysis',
      'enddata',
      'endstext',
      'mode',
      'nextdata',
      'par',
      'tot'
  ]
  
  FCS_STANDARD_OPTIONAL_KEYWORDS = [
      'abrt',
      'btim',
      'cells',
      'com',
      'csmode',
      'csvbits',
      'cyt',
      'cytsn',
      'date',
      'etim',
      'exp',
      'fil',
      'gate',
      'inst',
      'last_modified',
      'last_modifier',
      'lost',
      'op',
      'originality',
      'plateid',
      'platename',
      'proj',
      'smno',
      'spillover',
      'src',
      'sys',
      'timestep',
      'tr',
      'vol',
      'wellid'
  ]
  
  FCS_STANDARD_KEYWORDS = FCS_STANDARD_REQUIRED_KEYWORDS + FCS_STANDARD_OPTIONAL_KEYWORDS
  
subject: add fcs_keywords containing FCS standard keyword lists