Check if expection is raised with pytest [duplicate]

This question already has an answer here:

• How to properly assert that an exception gets raised in pytest? 5 answers

Being quite new to exception test handling I am wondering how to check if an assertion is raised.

a.py

class SomeError(Exception):
    pass

class SomeClass(object):
    def __init__(self):
        ...
        raise SomeError
        ...

test_a.py

from a.a import SomeClass

def test_some_exception_raised():
    ?

What assertion should it be there to check if SomeError is raised? I am using pytest.