'Get all values for a header.
This returns a list of values for headers given more than once; each
value in the result list is stripped in the same way as the result of
getheader().  If the header is not given, return an empty list.'

def getheaders(self, name):

    result = []
    current = ''
    have_header = 0
    for s in self.getallmatchingheaders(name):
        if s[0].isspace():
            if current:
                current = ('%s\n    %s' % (current, s.strip()))
            else:
                current = s.strip()
        else:
            if have_header:
                result.append(current)
            current = s[(s.find(':') + 1):].strip()
            have_header = 1
    if have_header:
        result.append(current)
    return result
