Functions are used to transform, combine, and perform computations on :term:`series` data. Functions are
applied using the Composer interface or by manipulating the
target parameters in the
:doc:`URL API <url-api>`.
Most functions are applied to one :term:`series list`. Functions with the parameter
*seriesLists can take an arbitrary number of series lists. To pass multiple series lists
to a function which only takes one, use the :py:func:`group` function.