[{'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:def make_seaborn(x_old, y_old,  z_old):\nx_sns = x_old[0:-1]      # remove last entry in x-corrd array\ny_sns = y_old[-1:0:-1]   # remove first entry, reverse order in y-coord array\nm,n = z_old.shape        # get dimension of original array\ntmp = np.empty((m,n))    # init. tmp array\ntmp.fill(np.nan)         #   with NaNs\nfor i in range(m):             # loop through rows\ntmp[i,0:i] = z_old[i,0:i]  # add items below the diagonal\ntmp = np.flipud(tmp)     #  reverse order of all columns in tmp array\nz_sns = tmp  # copy tmp array to outpur variable\nreturn (x_sns,y_sns,z_sns)  # return new coodinates in tuple'}, {'role': 'assistant', 'content': 'data_preprocessing'}]