public boolean removeKey(String key) {
        synchronized (this.confData) {
            boolean removed = this.confData.remove(key) != null;
            removed |= removePrefixMap(confData, key);
            return removed;
        }
    }
@TestTemplate
    void testRemoveKey() {
        Configuration cfg = new Configuration(standardYaml);
        String key1 = "a.b";
        String key2 = "c.d";
        cfg.setInteger(key1, 42);
        cfg.setInteger(key2, 44);
        cfg.setInteger(key2 + ".f1", 44);
        cfg.setInteger(key2 + ".f2", 44);
        cfg.setInteger("e.f", 1337);

        assertThat(cfg.removeKey("not-existing-key")).isFalse();
        assertThat(cfg.removeKey(key1)).isTrue();
        assertThat(cfg.containsKey(key1)).isFalse();

        assertThat(cfg.removeKey(key2)).isTrue();
        assertThat(cfg.keySet()).containsExactlyInAnyOrder("e.f");
    }