def _get_full_title(self):
        """Determines the title for the need in order of precedence:
        directive argument, first sentence of requirement (if
        `:title_from_content:` was set, and '' if no title is to be derived."""
        if len(self.arguments) > 0:  # a title was passed
            if 'title_from_content' in self.options:
                self.log.warning(
                    'Needs: need "{}" has :title_from_content: set, '
                    'but a title was provided. (see file {})'
                        .format(self.arguments[0], self.docname)
                )
            return self.arguments[0]
        elif self.title_from_content:
            first_sentence = ' '.join(self.content).split('.', 1)[0]
            if not first_sentence:
                raise NeedsInvalidException(':title_from_content: set, but '
                                            'no content provided. '
                                            '(Line {} of file {}'
                                            .format(self.lineno, self.docname))
            return first_sentence
        else:
            return ''
Determines the title for the need in order of precedence:
        directive argument, first sentence of requirement (if
        `:title_from_content:` was set, and '' if no title is to be derived.