code: def size(self):
          
          N = self.nmax + 1;
          NC = N + self.mmax * (2 * N - self.mmax - 1);
          assert NC == len(self._vec)
          return NC
docs: Total number of coefficients in the ScalarCoefs structure.
  
          Example::
  
              >>> sz  = c.size
              >>> N = c.nmax + 1
              >>> L = N+ c.mmax * (2 * N - c.mmax - 1);
              >>> assert sz == L