code: def _call(self, x):
          
          # Lazy import to improve `import odl` time
          import scipy.special
  
          with np.errstate(invalid='ignore', divide='ignore'):
              if self.prior is None:
                  res = (x - 1 - np.log(x)).inner(self.domain.one())
              else:
                  xlogy = scipy.special.xlogy(self.prior, self.prior / x)
                  res = (x - self.prior + xlogy).inner(self.domain.one())
  
          if not np.isfinite(res):
              # In this case, some element was less than or equal to zero
              return np.inf
          else:
              return res
docs: Return the KL-diveregnce in the point ``x``.
  
          If any components of ``x`` is non-positive, the value is positive
          infinity.