public SearchManager add(SchemaDef schema) {
        if (this.schema.containsKey(schema.getName())) {
            throw new IllegalArgumentException("There already exist a schema with this content:\n" +
                                               this.schema.get(schema.getName()).toString() + "\n No room for : " + schema);
        }
        this.schema.put(schema.getName(), schema);
        return this;
    }
Adds a schema or throw an IllegalArgumentException if the name is already used

@param schema the schema to add
@return itself for chaining purposes.
config-model/src/main/java/com/yahoo/vespa/documentmodel/SearchManager.java