code: def dvnorm(state):
      
      assert len(state) is 6
      state = stypes.toDoubleVector(state)
      return libspice.dvnorm_c(state)
docs: Function to calculate the derivative of the norm of a 3-vector.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/dvnorm_c.html
  
      :param state:
                  A 6-vector composed of three coordinates and their derivatives.
      :type state: 6-Element Array of floats
      :return: The derivative of the norm of a 3-vector.
      :rtype: float