rest-assured/src/main/java/io/restassured/internal/MultiValueEntity.java
public String getValue(String entityName) {
        notNull(entityName, "Entity name");
        final T entity = get(entityName);
        if(entity == null) {
            return null;
        }
        return entity.getValue();
    }
public String getValue(String entityName) {
        notNull(entityName, "Entity name");
        final T entity = get(entityName);
        if(entity == null) {
            return null;
        }
        return entity.getValue();
    }
Get a single entity value with the supplied name. If there are several headers match the <code>headerName</code> then
the last one is returned.

@param entityName The name of the header to find
@return The found entity value or <code>null</code> if no header was found.