can't create new mailer

apps/mailer/forms.py throws exception "string index must be numeric" in line 110.

Happens at least in version 2.7.0 and 2.7.1

probable fix: replace

        for field in self.schema['fields']:                                                                                                                                                                                                                            
            backend_data[field['name']] = data.pop(                                                                                                                                                                                                                    
                field['name'], field.get('default', None)                                                                                                                                                                                                              
            )                                                                                                                                                                                                                                                          

with

        for field_name, field_data in self.schema['fields'].items():
            backend_data[field_name] = data.pop(
                field_name, field_data.get('default', None)
            )