expose error_estimate

Author: thrasibule

quantlib/_instrument.pxd

@@ -11,6 +11,7 @@ cdef extern from 'ql/instrument.hpp' namespace 'QuantLib':
         Instrument()
         bool isExpired()
         Real NPV() except +
+        Real errorEstimate() except +
         Date& valuationDate() except +
         void setPricingEngine(shared_ptr[PricingEngine]&)
         T result[T](const string& tag)

quantlib/instrument.pyx

@@ -25,6 +25,11 @@ cdef class Instrument(Observable):
         def __get__(self):
             return self._thisptr.get().NPV()
 
+    @property
+    def error_estimate(self) -> Real:
+        """error estimate on the NPV when available"""
+        return self._thisptr.get().errorEstimate()
+
     property npv:
         """ Shortcut to the net_present_value property. """
         def __get__(self):