def errorhandle(self, resp):            
        if self.format == 'json':
            parsed = xmltodict.parse(resp)
            errors = parsed[self.RESPONSE_TOKEN][self.ERROR_TOKEN]
            if type(errors) is list and len(errors) > 1:
                messages = ", ".join([" ".join(["{}: {}".format(k,v) for k, v in e.items()]) for e in errors])
            else:
                overlimit = any('transaction limit' in msg.lower() for msg in errors.values())
                if overlimit:
                    raise APILimitExceeded("This API key has used up its daily quota of calls.")
                else:    
                    messages = " ".join(["{}: {}".format(k,v) for k, v in errors.items()])    
        elif self.format == 'xml':
            import xml.etree.ElementTree as ET
            errors = ET.fromstring(resp).findall(self.ERROR_TOKEN)
            messages = ", ".join(err.find('msg').text for err in errors)
        else:
            raise ValueError("Invalid API response format specified: {}." % self.format)        
        raise BustimeError("API returned: {}".format(messages))