code: def validate_yaml(self, properties):
          
          validator = OurValidator(schema)
          if not validator.validate(properties):
              for key, value in validator.errors.items():
                  if any(['unallowed value' in v for v in value]):
                      print(('{key} has an illegal value. Allowed values are {values} and are case '
                             'sensitive.').format(key=key, values=schema[key]['allowed']))
  
              raise ValueError(validator.errors)
docs: Validate the parsed YAML file for adherance to the ChemKED format.
  
          Arguments:
              properties (`dict`): Dictionary created from the parsed YAML file
  
          Raises:
              `ValueError`: If the YAML file cannot be validated, a `ValueError` is raised whose
                  string contains the errors that are present.