def api_activity_histogram(self,app_id,exp_uid,task):
    """
    Description: returns the data to plot all API activity (for all algorithms) in a histogram with respect to time for any task in {getQuery,processAnswer,predict} 

    Expected input:
      (string) task :  must be in {'getQuery','processAnswer','predict'}

    Expected output (in dict):
      (dict) MPLD3 plot dictionary
    """


    list_of_log_dict,didSucceed,message = self.ell.get_logs_with_filter(app_id+':APP-CALL',{'exp_uid':exp_uid,'task':task})

    from datetime import datetime
    from datetime import timedelta
    start_date_str,didSucceed,message = self.db.get('experiments_admin',exp_uid,'start_date')
    start_date = utils.str2datetime(start_date_str)
    numerical_timestamps = [ ( start_date-utils.str2datetime(item['timestamp'])).total_seconds() for item in list_of_log_dict]

    import matplotlib.pyplot as plt
    import mpld3
    fig, ax = plt.subplots(subplot_kw=dict(axisbg='#FFFFFF'),figsize=(12,1.5))
    ax.hist(numerical_timestamps,int(1+4*numpy.sqrt(len(numerical_timestamps))),alpha=0.5,color='black')
    ax.set_frame_on(False)
    ax.get_xaxis().set_ticks([])
    ax.get_yaxis().set_ticks([])
    ax.get_yaxis().set_visible(False)
    ax.set_xlim(0, max(numerical_timestamps))
    plot_dict = mpld3.fig_to_dict(fig)

    
    return plot_dict
dataset/ETHPy150Open nextml/NEXT/next/dashboard/AppDashboard.py/AppDashboard.api_activity_histogram/swapped operands of `-`