inFeatures = "MyLayer"
fields = ['x','y']

# Add fields to your inFeatures
for field in fields:
    arcpy.AddField_management(inFeatures,str(field),"DOUBLE")

with arcpy.da.UpdateCursor(inFeatures, ('x','y',"shape@")) as cursor:
    for row in cursor:
        row[0] = row[2].firstPoint.X
        row[1] = row[2].lastPoint.X
        cursor.updateRow(row)