code: def get_field_errors(node):
          
          assert node.name() == 'securityData' and not node.isArray()
          nodearr = node.getElement('fieldExceptions')
          if nodearr.numValues() > 0:
              secid = XmlHelper.get_child_value(node, 'security')
              errors = XmlHelper.as_field_error(nodearr, secid)
              return errors
          else:
              return None
docs: return a list of FieldErrors if the specified securityData element has field errors