Question: I am using a `TabNavigator` in my react-native project, and pass some data between the screens via `this.props.navigation.setParams()`, and respectively `this.props.navigation.getParam()`. The problem is that this approach works for me, only when I send that data for the first time, second time when I try to send the data, when leaving the screen the data doesn't update in `navigation.state.params`

Here are fragments of code responsible for receiving, and sending data

```
import {NavigationEvents} from 'react-navigation';

...

receiveData = () => {
    if (this.props.navigation.state.params.data !== null) {
        const data = this.props.navigation.getParam('data');
        this.setState({data});
    }
}

sendData = () => {
    const {data} = this.state;
    this.props.navigation.setParams({data});
}

render(){

...

<NavigationEvents
    onWillFocus = {this.receiveData}
    on WillBlur = {this.sendData}
/>

...

}

```

Answer: 
You need to set the seed inside your processes:

```
import random
from multiprocessing import Process, Manager

def f2(i):
    random.seed(2019+i)
    print('from f2:')
    v = random.randint(0, 10)
    a = random.randint(0, 10)
    print('v:', v, 'a:', a)
    return v, a

def python_process_test():
    n_workers = 2
    workers = []

    for i in range(n_workers):
        p = Process(target=f2, args=([i]))
        p.start()
        workers.append(p)

    for p in workers:
        p.join()

if __name__ == '__main__':
    python_process_test()

```

This yield the following output everytime:

```
from f2:
v: 2 a: 3
from f2:
v: 9 a: 9

```

EDIT: updated to show the passthrough of reseeding each process by worker with different seeds
A simple fix, so no worries:

**If you want to generate the same number every time you need to pass the same seed value every time. [1](https://pynative.com/python-random-seed/)**

So all you need to do is call `random.seed(2019)` before every `randint()`.

Essentially, every time you use the random module to obtain a value, it pulls the `.seed()` value from the current system time. So you'll have to manually set the seed each time, or else it'll default back to that behavior.