Here is how you need to call in various scenarios,
In case of activity:

ContextCompat.checkSelfPermission(MyActivity.this, Manifest.permission.READ_CONTACTS);
In case of fragment:

ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.READ_CONTACTS);
In case of any utility class use context:

ContextCompat.checkSelfPermission(context, Manifest.permission.READ_CONTACTS);
for more depth, you can refer to https://developer.android.com/training/permissions/requesting

Here is how you need to call in various scenarios,
In case of activity:
ContextCompat.checkSelfPermission(MyActivity.this, Manifest.permission.WRITE_CALENDAR); In case of fragment:
ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.WRITE_CALENDAR);
In case of any utility class use context:
ContextCompat.checkSelfPermission(context, Manifest.permission.WRITE_CALENDAR);

Comment below for further information