def parse(self, request, bundle_errors=False):
        """Parses argument value(s) from the request, converting according to
        the argument's type.

        :param request: The flask request object to parse arguments from
        :param bundle_errors: Do not abort when first error occurs, return a
            dict with the name of the argument and the error message to be
            bundled
        """
        source = self.source(request)

        results = []

        # Sentinels
        _not_found = False
        _found = True

        for operator in self.operators:
            name = self.name + operator.replace("=", "", 1)
            if name in source:
                # Account for MultiDict and regular dict
                if hasattr(source, "getlist"):
                    values = source.getlist(name)
                else:
                    values = source.get(name)
                    if not (isinstance(values, collections.MutableSequence) and self.action == 'append'):
                        values = [values]

                for value in values:
                    if hasattr(value, "strip") and self.trim:
                        value = value.strip()
                    if hasattr(value, "lower") and not self.case_sensitive:
                        value = value.lower()

                        if hasattr(self.choices, "__iter__"):
                            self.choices = [choice.lower()
                                            for choice in self.choices]

                    try:
                        value = self.convert(value, operator)
                    except Exception as error:
                        if self.ignore:
                            continue
                        return self.handle_validation_error(error, bundle_errors)

                    if self.choices and value not in self.choices:
                        if current_app.config.get("BUNDLE_ERRORS", False) or bundle_errors:
                            return self.handle_validation_error(
                                ValueError(u"{0} is not a valid choice".format(
                                    value)), bundle_errors)
                        self.handle_validation_error(
                                ValueError(u"{0} is not a valid choice".format(
                                    value)), bundle_errors)

                    if name in request.unparsed_arguments:
                        request.unparsed_arguments.pop(name)
                    results.append(value)

        if not results and self.required:
            if isinstance(self.location, six.string_types):
                error_msg = u"Missing required parameter in {0}".format(
                    _friendly_location.get(self.location, self.location)
                )
            else:
                friendly_locations = [_friendly_location.get(loc, loc)
                                      for loc in self.location]
                error_msg = u"Missing required parameter in {0}".format(
                    ' or '.join(friendly_locations)
                )
            if current_app.config.get("BUNDLE_ERRORS", False) or bundle_errors:
                return self.handle_validation_error(ValueError(error_msg), bundle_errors)
            self.handle_validation_error(ValueError(error_msg), bundle_errors)

        if not results:
            if callable(self.default):
                return self.default(), _not_found
            else:
                return self.default, _not_found

        if self.action == 'append':
            return results, _found

        if self.action == 'store' or len(results) == 1:
            return results[0], _found
        return results, _found