class_docstr: Measurement process that computes the expectation value of the supplied observable.
  
  Please refer to :func:`expval` for detailed documentation.
  
  Args:
      obs (Union[.Operator, .MeasurementValue]): The observable that is to be measured
          as part of the measurement process. Not all measurement processes require observables
          (for example ``Probability``); this argument is optional.
      wires (.Wires): The wires the measurement process applies to.
          This can only be specified if an observable was not provided.
      eigvals (array): A flat array representing the eigenvalues of the measurement.
          This can only be specified if an observable was not provided.
      id (str): custom label given to a measurement instance, can be useful for some applications
          where the instance has to be identified
code: def numeric_type(self):
      return float
  
file_path: pennylane/pennylane/measurements/expval.py
imports: import warnings
  from typing import Sequence, Tuple, Union
  import pennylane
  from pennylane.operation import Operator
  from pennylane.wires import Wires
  from .measurements import Expectation, SampleMeasurement, StateMeasurement
  from .mid_measure import MeasurementValue
label_desc: Use image node_id 2 for calling the ExpectationMP obj's underlying member method code with example usage: obj.numeric_type() and returns: float