def valid(self):
    if (not self.value):
        return True
    if (('@' in self.value) and ('.' in self.value) and (self.value.find('.', self.value.find('@')) > 0) and (self.value.count('@') == 1) and (self.value.find('..') == (- 1))):
        return True
    else:
        return ('Not a valid email format: %s' % self.value)
def valid(self):
    if (not self.value):
        return True
    if (('@' in self.value) and ('.' in self.value) and (self.value.find('.', self.value.find('@')) > 0) and (self.value.count('@') == 1) and (self.value.find('..') == (- 1))):
        return True
    else:
        return ('Not a valid email format: %s' % self.value)