pcapy - print the DATA field of a packet

[billiejoex]

Hi all. I'm using pcapy module to sniff some ICMP packets. I would like to 
modify this source:
http://www.google.it/search?hl=it&q=pcapy&btnG=Cerca+con+Google&meta=
and visualize only the DATA filed of the sniffed packets instead of all 
fields that are generally visualized (for example: ip src, ip dest, packet 
type...)
For example in this sniffing output:

ICMP type: ECHOREPLY code: UNKNOWN

6efb bf0d 0800 4500 0027 9c42 0000 ff01    n.....E..'.B....
72eb 29ff 0459 2907 5549 0000 9942 0001    r.)..Y).UI...B..
0000 6e65 7473 7461 7420 2d61 6e           ..Hello world!

... I would like to visualize the 'Hello world' string only.
Sorry for my bad english.

Best regards.