Gets the measurement key strings of measurements within the given value.
) -> AbstractSet[str]
The value which has the measurement key.
Defaults to True. When true, composite operations that
don't directly specify their measurement keys will be decomposed in
order to find measurement keys within the decomposed operations. If
not set, composite operations will appear to have no measurement
keys. Used by internal methods to stop redundant decompositions from
The measurement keys of the value. If the value has no measurement,
the result is the empty set.