code: def nu2lambda(nu):
      """
      Convert optical frequency to wavelength.
  
      Parameters
      ----------
      nu : array_like
          Optical frequency to be converted.
  
      Returns
      -------
      lambda : float or array of floats
          Equivalent wavelength(s).
  
      Notes
      -----
      Computes ``lambda = c / nu`` where c = 299792458.0, i.e., the
      (vacuum) speed of light in meters/second.
  
      Examples
      --------
      >>> from scipy.constants import nu2lambda, speed_of_light
      >>> nu2lambda(np.array((1, speed_of_light)))
      array([  2.99792458e+08,   1.00000000e+00])
  
      """
      return c / _np.asanyarray(nu)
  
imports: import math
  from .codata import value
  import numpy
label_desc: Use image node_id 3 for calling a global function with example usage: nu2lambda(nu) and returns: unknown