loadFastaDna usage not obvious due to default method parameter

[heuermh]

ADAMContext includes the following methods for loading data into SequenceDataset and SliceDataset

  // load FASTA as DNA

  def loadFastaDna(pathName: String): SequenceDataset = {}

  def loadFastaDna(
    pathName: String,
    maximumLength: Long = 10000L): SliceDataset = {}

  // format guessing, including FASTA and Parquet

  def loadDnaSequences(
    pathName: String,
    optPredicate: Option[FilterPredicate] = None,
    optProjection: Option[Schema] = None): SequenceDataset = {}

  def loadSlices(
    pathName: String,
    maximumLength: Long = 10000L,
    optPredicate: Option[FilterPredicate] = None,
    optProjection: Option[Schema] = None): SliceDataset = {}

  // data frames

  def loadSequences(df: DataFrame): SequenceDataset = {}

  def loadSequences(df: DataFrame, metadataPathName: String): SequenceDataset = {}

  def loadSequences(
    df: DataFrame,
    references: SequenceDictionary): SequenceDataset = {}

  def loadSlices(df: DataFrame): SliceDataset = {}

  def loadSlices(df: DataFrame, metadataPathName: String): SliceDataset = {}

  def loadSlices(
    df: DataFrame,
    references: SequenceDictionary): SliceDataset = {}

This method, which uses a default maximumLength method parameter

  def loadFastaDna(
    pathName: String,
    maximumLength: Long = 10000L): SliceDataset = {}

is not obviously different from

  def loadFastaDna(pathName: String): SequenceDataset = {}

especially in the Spark shell environment. Perhaps we should drop the default value for maximumLength in the loadFastaDna method that returns SliceDataset.