def __parse_dois(self, x):
        """
        Parse the Dataset_DOI field. Could be one DOI string, or a list of DOIs
        :param any x: Str or List of DOI ids
        :return none: list is set to self
        """
        # datasetDOI is a string. parse, validate and return a list of DOIs
        if isinstance(x, str):
            # regex cleans string, and returns a list with 1 entry for each regex doi match
            m = clean_doi(x)
            # make sure m is not an empty list
            if m:
                # set list directly into self
                self.doi = m

        # datasetDOI is a list. use regex to validate each doi entry.
        elif isinstance(x, list):
            for entry in x:
                # regex cleans string, and returns a list with 1 entry for each regex doi match
                m = clean_doi(entry)
                # make sure m is not an empty list
                if m:
                    # combine lists with existing self list
                    self.doi += m
        return
Parse the Dataset_DOI field. Could be one DOI string, or a list of DOIs
        :param any x: Str or List of DOI ids
        :return none: list is set to self