code: def _createShapelet(self,coeff):
          
          n_coeffs = len(coeff)
          num_l = self._get_num_l(n_coeffs)
          shapelets=np.zeros((num_l+1,num_l+1),'complex')
          nl=0
          k=0
          i=0
          while i < len(coeff):
              if i%2==0:
                  shapelets[nl][k]+=coeff[i]/2.
                  shapelets[k][nl]+=coeff[i]/2.
                  if k==nl:
                      nl+=1
                      k=0
                      i+=1
                      continue
                  else:
                      k+=1
                      i+=1
                      continue
              else:
                  shapelets[nl][k] += 1j*coeff[i]/2.
                  shapelets[k][nl] -= 1j*coeff[i]/2.
                  i+=1
          return shapelets
docs: returns a shapelet array out of the coefficients *a, up to order l
  
          :param num_l: order of shapelets
          :type num_l: int.
          :param coeff: shapelet coefficients
          :type coeff: floats
          :returns:  complex array
          :raises: AttributeError, KeyError