def bulkImport_json(self, filename, onDuplicate="error", formatType="auto", **params) :
        """bulk import from a file repecting arango's key/value format"""

        url = "%s/import" % self.database.URL
        params["onDuplicate"] = onDuplicate
        params["collection"] = self.name
        params["type"] = formatType
        with open(filename) as f:
            data = f.read()
            r = self.connection.session.post(URL, params = params, data = data)

            try :
                errorMessage = "At least: %d errors. The first one is: '%s'\n\n more in <this_exception>.data" % (len(data), data[0]["errorMessage"])
            except KeyError:
                raise UpdateError(data['errorMessage'], data)
bulk import from a file repecting arango's key/value format