 string, optional, set the starting date or time of the series
using "YYYY-MM-DD" format for date and "YYYY-MM-DDTHH" format for hourly time series</p></dd>
<dt>end</dt>
<dd><p>A string, optional, set the ending date or time of the series
using "YYYY-MM-DD" format for date and "YYYY-MM-DDTHH" format for hourly time series</p></dd>
<dt>length</dt>
<dd><p>An integer, optional, defines the length of the series, if set to
NULL (default), will default to the API default value of 5000 observations per
pull. The A