Sending native tez to one or multiple address

Development
1

The following question has been asked on Telegram:

Can u send tokens to other people’s wallets in smartpy for example keep a map of everyone that has purchased tokens the. send a percentage of tokens to them on another entry point?

2

You can use sp.send(<receiver>, <amount>) to send tokens to wallets but pay attention to the sending to multiple addresses flaw described here: https://opentezos.com/smart-contracts/avoiding-flaws/#2-transferring-tez-in-a-call-that-should-benefits-others.

The best practice is to create a withdraw entrypoint so anyone can withdraw its tokens.
For example:

import smartpy as sp

@sp.module
def main():
    class MyContract(sp.Contract):
        def __init__(self, receivers):
            sp.cast(receivers, sp.big_map[sp.address, sp.mutez])
            self.data.receivers = receivers

        @sp.entrypoint
        def withdraw(self):
            amount = self.data.receivers.get(sp.sender, error="NotInReceivers")
            sp.send(sp.sender, amount)
            del self.data.receivers[sp.sender]

if "templates" not in __name__:
    @sp.add_test(name="MyContract")
    def test():
        alice = sp.test_account("alice")
        sc = sp.test_scenario(main)
        receivers = sp.big_map({alice.address: sp.tez(5)})
        c1 = main.MyContract(receivers)
        c1.set_initial_balance(sp.tez(20))
        sc += c1
        c1.withdraw().run(sender=alice)