def _parse_request(self, schema, req, locations):
        """Return a parsed arguments dictionary for the current request."""
        if schema.many:
            assert (
                "json" in locations
            ), "schema.many=True is only supported for JSON location"
            # The ad hoc Nested field is more like a workaround or a helper,
            # and it servers its purpose fine. However, if somebody has a desire
            # to re-design the support of bulk-type arguments, go ahead.
            parsed = self.parse_arg(
                name="json",
                field=ma.fields.Nested(schema, many=True),
                req=req,
                locations=locations,
            )
            if parsed is missing:
                parsed = []
        else:
            argdict = schema.fields
            parsed = {}
            for argname, field_obj in iteritems(argdict):
                if MARSHMALLOW_VERSION_INFO[0] < 3:
                    parsed_value = self.parse_arg(argname, field_obj, req, locations)
                    # If load_from is specified on the field, try to parse from that key
                    if parsed_value is missing and field_obj.load_from:
                        parsed_value = self.parse_arg(
                            field_obj.load_from, field_obj, req, locations
                        )
                        argname = field_obj.load_from
                else:
                    argname = field_obj.data_key or argname
                    parsed_value = self.parse_arg(argname, field_obj, req, locations)
                if parsed_value is not missing:
                    parsed[argname] = parsed_value
        return parsed
Return a parsed arguments dictionary for the current request.