[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify code snippets into one of the following categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']."}, {'role': 'user', 'content': 'Identify the single most appropriate category to which the provided code belongs. Provide your response as a single category label without any additional information, commentary, or personal opinions.\\nPython Code:# function to bin the timestamp in time of day\n\ndef bintod(x):\n    if x < 3:\n        return 0\n    elif x < 8:\n        return 1\n    elif x < 20:\n        return 2\n    elif x < 23:\n        return 3\n    else:\n        return 0 \n# functions to assign region based on latitude and longitude\ndef lngregion(x):\n    if x < 80:\n        return 1\n    elif x < 90:\n        return 2\n    elif x < 100:\n        return 3\n    elif x < 110:\n        return 4\n    elif x < 120:\n        return 5\n    elif x < 130:\n        return 6\n    elif x < 140:\n        return 7\n    else:\n        return 0\nnlng = 8\nnlat = 9\ndef latregion(x):\n    if x < 20:\n        return 1\n    elif x < 25:\n        return 2\n    elif x < 30:\n        return 3\n    elif x < 35:\n        return 4\n    elif x < 40:\n        return 5\n    elif x < 45:\n        return 6\n    elif x < 50:\n        return 7\n    elif x < 55:\n        return 8    \n    else:\n        return 0      '}, {'role': 'assistant', 'content': 'data_preprocessing'}]