public Number getNumberMemberOrDefault(String memberName, Number defaultValue) {
        return getNumberMember(memberName).map(NumberNode::getValue).orElse(defaultValue);
    }
Gets the member with the given name, and if present, expects it to
be a number, otherwise returns the default value.

@param memberName Name of the member to get.
@param defaultValue Default value to return if a member is not found.
@return Returns the Number value or a default value.
@throws ExpectationNotMetException if the member is not a number.
smithy-model/src/main/java/software/amazon/smithy/model/node/ObjectNode.java