"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

     * @param artifactId never {@code null}
     * @param version can be {@code null}
     * @return the matching model or {@code null}
     * @throws IllegalStateException if version was null and multiple modules share the same groupId + artifactId
     */
    public Model get(String groupId, String artifactId, String version) {
        return modelsByGa.getOrDefault(new GAKey(groupId, artifactId), Collections.emptySet()).stream()