OptionError: optparse.py invalid action: error

OptionError: optparse.py invalid action: error

Greetings I am receiving an error when I attempt to place arguments into
my python script. Here is the function
from optparse import OptionParser
def getparams():
usage = "usage: %prog -d <dcb_ip> -p <port> "
parser = OptionParser(usage)
parser.add_option("-d", "--dcb_ip",
action="store",
dest="dcb_ip",
default="172.14.20.31",
help="Specifiy the IP address of the device, default is
[%default].")
parser.add_option("-p", "--port",
action="store",
type="int",
dest="port",
default=51500,
help="Specify the pcl port of the monitor, default is
[%default].")
parser.add_option("-i", "--interactive", action="store_true",
default=False, dest="interactive")
parser.add_option("-l", "--loop", action="store", default=False,
dest="loop")
parser.add_option("-w", "--write", action="write_mem", default=False,
dest="interactive") #Write HART option
parser.add_option("-r", "--read", action="read_mem", default=False,
dest="interactive")
parser.add_option("-c", "--Cancel", action="cancel_mem", default=False,
dest="interactive")
(options, args) = parser.parse_args(sys.argv)
return options
Does anyone know why I keep getting
'Traceback (most recent call last):
File "C:\Users\Documents\devices_15_JUL_2013\RSimulator.py", line 73, in
getparams
parser.add_option("-w", "--write", action="write_mem", default=False)
#Write mem option
OptionError: option -w/--write: invalid action: 'write_mem''
I thought -c might be a common option or something but even when I changed
it still did not work :(
Thanks ``