Add __enter__ and __exit__ methods to QMI_Instrument

[rbudhrani]

Description

By adding these two methods an instrument class can provide its own Context manager without needing the wrapping call to open_close().

Proposal:
Add enter and exit method to QMI_Instrument.

class QMI_Instrument(QMI_RpcObject):
    ...
    @rpc_method
    def __enter__(self):
        self.open()
        return self
    
    @rpc_method
    def __exit__(self):
        self.close()

Also add them to the RPC proxy

class QMI_RpcProxy:
    ...
    def __enter__(self):
        self.__enter__()
        return self

    def __exit__(self, *args, **kwargs):
        self.__exit__()

Then you can do the following:

with qmi.make_instrument(...) as instr:
    instr.do_something()

Since QMI_RpcProxy could also be the client for a QMI_RpcObject, we must define the __enter__ and __exit__ methods in QMI_RpcProxy and throw the NotImplementedError, so when a client uses the with statement they are are made aware of the fact that the QMI_RpcObject does not support context management.

Modules to be created

• n/a

Modules to be modified

• qmi.core.rpc
• qmi.core.instrument

Tests to be created/updated

• unittests

Documentation to be updated

• n/a

Hardware

• n/a