ArcPy.mp Get Selected Features Extent

EmmaBell-Carruthers1

I am trying to get the extent of the selected features in arcpy to pass into CreateFishnet. Currently I have it working so it will only create a fishnet for the last selected feature because it is just looping through the rows of the features. I have copied the code below. Any help would  be great. 

import arcpy


arcpy.env.overwriteOutput = True

cellSize = 50
sa = 2500
fullPlots = 0
halfPlots = 0

blockNum = arcpy.da.SearchCursor("L3OpSilv", "BLOCK_").next()[0]
whereClause = "BLOCK_ = '{0}'".format(blockNum)
#arcpy.AddMessage(whereClause)
with arcpy.da.SearchCursor('L3OpSilv', ["BLOCK_","SHAPE@"], whereClause) as rows:
    for row in rows:
        pLowerLeft = str(row[1].extent.lowerLeft)
        pUpperRight = str(row[1].extent.upperRight)
        fullExtent = row[1].extent
        extXMin = row[1].extent.XMin
        #arcpy.AddMessage(row[1].extent.YMin)
        extYMin = str(row[1].extent.YMin + 10)
        #arcpy.AddMessage(extYMin)
yAxisCoord = (str(extXMin) + " " + str(extYMin))

arcpy.management.CreateFishnet('fullextentfishnet', pLowerLeft, yAxisCoord, cellSize, cellSize, None, None, pUpperRight, 'NO_LABELS', fullExtent, 'Polygon')
fishnetclipped = arcpy.Clip_analysis('fullextentfishnet', 'L3OpSilv', 'fishnetclip')

Jack_Zhang

Thanks for the solution. I agree found it's very inconvenient to lose some of the basic functions in arcpy.mapping module , which makes it unnecessarily difficult to deal with the layer-type result returned by the Toolbox arcpy functions.