===FetchHistory===

The **FetchHistory** function of the [[mplreport]] class returns an [[AQLHistResponse]] object with the results of a historical AQL query. 

==Parameters==

^Parameter^Type^Default^Meaning^
|query|str||The AQL query to run, //without// the GETHISTORY command.|
|start|DateTime|None|The start of the query time, in UTC. If //None//, the report start time is used.|
|end|DateTime|None|The end of the query time, in UTC. If //None//, the report end time is used.|
|samples|int|2000|The number of samples to return. Ignored if **method** is //raw//.|
|method|str|interp|The query method. Can be //interp//,//min//,//max// or //raw//.|
|utc|bool|false|If //true//, result times are in UTC. If //false//, result times are in local time.|

==Return==

This function returns //None// on failure, or a **AQLHistResponse** object.

The AQLHistResponse has a member called 'data' which contains a Pandas dataframe containing all of the query results.

===Usage===

If this information is required for your report, we suggest calling [[FailOnError]] immediately after using this function.

==Example==

<code python>
#Get the history of all temperatures across the system
hist = report.FetchHistory("'Temperature' PROPERTY ALLPOINTS")
report.FailOnError('Temperature')

#Get the dataframe from that history...
df = hist.data

#For each column, plot a line-chart.
for col in df.columns:
   ax.plot(df[col],label=col)

ax.legend()
</code>

//This code will request **every** temperature property for the report range and chart it.//