code: def coherent_state(a, phi=0, hbar=2.0):
      r"""Returns a coherent state.
  
      Args:
          a (complex) : the displacement
          phi (float): the phase
          hbar (float): (default 2) the value of :math:`\hbar` in the commutation
              relation :math:`[\x,\p]=i\hbar`
      Returns:
          array: the coherent state
      """
      alpha = a * cmath.exp(1j * phi)
      means = np.array([alpha.real, alpha.imag]) * math.sqrt(2 * hbar)
      cov = np.identity(2) * hbar / 2
      state = [cov, means]
      return state
  
imports: import math
  import cmath
  import numpy
  from scipy.special import factorial
  import pennylane
  from pennylane.ops import Identity
  from pennylane import Device
  from .._version import __version__
label_desc: Use image node_id 14 for calling a global function with example usage: coherent_state(a, phi, hbar) and returns: state