"""
    TimeSeries <: TS

Composite type to store time series.
"""
struct TimeSeries <: TS
    times::AbstractVector{<:SupportedTimeTypes}

    function TimeSeries(times)
        times = vec(times)
        return new(times)
    end
end


"""
    ground_process(ts::TS)::TimeSeries

Returns the TimeSeries associated to a TS.
"""
function ground_process(ts::TS)::TimeSeries
    ts = TimeSeries(ts.times)
    return ts
end