public static Format fromString(String value) {
            for (Format format : values()) {
                if (format.value.equals(value)) {
                    return format;
                }
            }

            return UNKNOWN;
        }
Create a {@code Format} from a string that would appear in a model.

<p>Any unknown value is returned as {@code Unknown}.

@param value Value from a trait or model.
@return Returns the Format enum value.
smithy-model/src/main/java/software/amazon/smithy/model/traits/TimestampFormatTrait.java