gistfile1.rb

# Not sure if we should throw an exception or not.

def self.sequences(*sequences)
  if sequences.any? && (sequences - SEQUENCES.keys).empty?
    @sequences = sequences
  else
    raise ArgumentError, "Invalid sequence" 
  end
  @sequences || [:in]
end

def self.sequences(*sequences)
  if sequences.any?
    @sequences = sequences & SEQUENCES.keys
    @sequences = nil unless @sequences.any?
  end
  @sequences || [:in]
end