Python: Get Letter Metadata with GetLetterDetails()

Simple script to fetch the details of a letter using the PostalMethods 
GetLetterDetails SOAP API call.
You must set your SOAP client with a reference to 
the PostalMethods Web Service: 
$ wsdl2py --url 
Detailed instructions available in the Python samples zip file
from postalmethods import client
print 'Testing GetLetterDetails...'
c = client.PmClient('USERNAME','PASSWORD')
result = c.getLetterDetails(letterId)
print str(result) 
Result = -3000 means that the data was successfully retrieved.
A negative value means an error occurred.
See the PostalMethods Status Codes: