code: def create_derived(params)
        spc = super
        spc.label ||= "#{label}_#{children.size}" if label
        spc.specimen_collection_group = specimen_collection_group
        # if the derived specimen is the same type as this parent specimen,
        # then decrement this parent's quantity by the derived specimen amount
        decrement_derived_quantity(spc) if specimen_type == spc.specimen_type
        spc
      end
docs: Delegate to {AbstractSpecimen#create_derived} and add a default label if necessary. The default label
   is this Specimen label appended with an underscore and the number of children, e.g. +TB-0023434_1+
   for the first child of a parent with label +TB-0023434+.