User Interface for filtering objects in Python

In my application I have a Job class as defined/outlined below. Instance of this job class represents a particular Job run, Job can have multiple checkpoints and each checkpoint can have multiple commands.

Job
 - JobName
 - [JobCheckpoint]
 - StartTime
 - EndTime
 - Status
 - ...

JobCheckpoint
 - JobCheckpointName
 - [JobCommand]
 - StartTime
 - EndTime
 - Status
 - ...

JobCommand
 - JobCommandName
 - [Command]
 - StartTime
 - EndTime
 - Status 
 - ...

At any given day there are like 100k different jobs that runs. I want to design a user interface in Python for querying these job objects. For example users want to query

1. Jobs that ran between x and y interval.
2. Jobs that run command x
3. Jobs in failed state.
4. All checkpoints/commands of a particular job.
5. And many more...

To solve this, I was thinking of providing following methods in user interface.

1. dict getJobs(Filter)
2. dict getCommands(Job)
3. dict getCheckpoints(Job)

I am not sure

1. How Filter class will look like?
2. Is returning dict correct or should I return proper Job object?
3. Should I take dict as an input or defined classes as an input.
4. Whether this is a best design.