"炭窝里的石灰" meaning in 漢語

{
  "categories": [
    {
      "kind": "other",
      "name": "待分類的漢語詞",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "歇后语",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "漢語",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "漢語",
  "lang_code": "zh",
  "pos": "proverb",
  "senses": [
    {
      "glosses": [
        "炭窝里的石灰　——　黑白分明"
      ],
      "id": "zh-炭窝里的石灰-zh-proverb-uJf2VWpk"
    }
  ],
  "tags": [
    "xiehouyu"
  ],
  "word": "炭窝里的石灰"
}

{
  "categories": [
    "待分類的漢語詞",
    "歇后语",
    "漢語"
  ],
  "lang": "漢語",
  "lang_code": "zh",
  "pos": "proverb",
  "senses": [
    {
      "glosses": [
        "炭窝里的石灰　——　黑白分明"
      ]
    }
  ],
  "tags": [
    "xiehouyu"
  ],
  "word": "炭窝里的石灰"
}