docs: def blackbody_spectral_radiance(T, wavelength):
      r'''Returns the spectral radiance, in units of W/m^2/sr/µm.
  
      .. math::
          I_{\lambda,blackbody,e}(\lambda,T)=\frac{2hc_o^2}
          {\lambda^5[\exp(hc_o/\lambda k T)-1]}
  
      Parameters
      ----------
      T : float
          Temperature of the surface, [K]
      wavelength : float
          Length of the wave to be considered, [m]
  
      Returns
      -------
      I : float
          Spectral radiance [W/(m^2*sr*m)]
  
      Notes
      -----
      Can be used to derive the Stefan-Boltzman law, or determine the maximum
      radiant frequency for a given temperature.
      
      Examples
      --------
      Checked with Spectral-calc.com, at [2]_.
  
      >>> blackbody_spectral_radiance(800., 4E-6)
      1311692056.2430143
      
      Calculation of power from the sun (earth occupies 6.8E-5 steradian of the
      sun):
          
      >>> from scipy.integrate import quad
      >>> rad = lambda l: blackbody_spectral_radiance(5778., l)*6.8E-5
      >>> quad(rad, 1E-10, 1E-4)[0]
      1367.9808043781559
  
      References
      ----------
      .. [1] Bergman, Theodore L., Adrienne S. Lavine, Frank P. Incropera, and
         David P. DeWitt. Introduction to Heat Transfer. 6E. Hoboken, NJ:
         Wiley, 2011.
      .. [2] Spectral-calc.com. Blackbody Calculator, 2015.
         http://www.spectralcalc.com/blackbody_calculator/blackbody.php
      '''
      try:
          return 2.*h*c**2/wavelength**5/(exp(h*c/(wavelength*T*k)) - 1.)
      except OverflowError:
          return 0.0