def grab_email(files = []):
# if passed a list of text files, will return a list of
# email addresses found in the files, matched according to
# basic address conventions. Note: supports most possible
# names, but not all valid ones.

found = []
if files != None:
    mailsrch = re.compile(r'[\w\-][\w\-\.]+@[\w\-][\w\-\.]+[a-zA-Z]{1,4}')

    for file in files:            
        for line in open(file,'r'):                
            found.extend(mailsrch.findall(line))    

# remove duplicate elements
# borrowed from Tim Peters' algorithm on ASPN Cookbook
u = {}
for item in found:
    u[item] = 1

# return list of unique email addresses
return u.keys()