I am using arcpy and while running the script it is unable to find RasterCalculator() method? Even after imporiting arpy module
>>> RasterCalculator("IDSI_2002.img + IDSI_2007.img","D:/PythonScripts/test.img")
Runtime error
Traceback (most recent call last):
File "<string>", line 1, in <module>
NameError: name 'RasterCalculator' is not defined
Calculator' is not defined