code: def _is_observable(x):
      """Predicate for deciding if an Operator instance is an observable.
  
      .. note::
         Currently some :class:`Observable` instances are not observables in this sense,
         since they can be used as gates as well.
  
      Args:
          x (Operator): node in the circuit graph
      Returns:
          bool: True iff x is an observable
      """
      return isinstance(x, MeasurementProcess)
  
imports: from numbers import Number
  from collections import namedtuple
  import numpy
  import rustworkx
  from pennylane.measurements import MeasurementProcess
  from pennylane.resource import ResourcesOperation
label_desc: Use image node_id 2 for calling a global function with example usage: _is_observable(x) and returns: isinstance