private String toIndentedString(Object o) {
		if (o == null) {
			return "null";
		}
		return o.toString().replace("\n", "\n    ");
	}
Convert the given object to string with each line indented by 4 spaces
(except the first line).

@param o the o
@return the string
springdoc-openapi-tests/springdoc-openapi-javadoc-tests/src/test/java/test/org/springdoc/api/v30/app90/User.java