          # self._features_table.get(features))
  
      def add_alias(self, unicode alias, entities, probabilities):
          """For a given alias, add its potential entities and prior probabilies to the KB."""
          cdef hash_t alias_hash = self.strings.add(alias)
  
          # Return if this alias was added before
          if alias_hash in self._alias_index:
              user_warning("Alias " + alias + " already exists in the KB")
              return
 
</s> remove     mykb.add_entity(entity_id="Q1", prob=0.5)
    mykb.add_entity(entity_id="Q2", prob=0.5)
 </s> add     mykb.add_entity(entity_id="Q1", prob=0.9)
    mykb.add_entity(entity_id="Q2", prob=0.2) </s> remove     mykb.add_entity(entity_id="Q1", prob=0.5)
    mykb.add_entity(entity_id="Q2", prob=0.5)
 </s> add     mykb.add_entity(entity_id="Q1", prob=0.9)
    mykb.add_entity(entity_id="Q2", prob=0.2)
        # Throw an error if the probabilities sum up to more than 1
        prob_sum = sum(probabilities)
        if prob_sum > 1:
            raise ValueError("The sum of prior probabilities for alias '" + alias + "' should not exceed 1, "
                                                                                    "but found " + str(prob_sum))

          # self._features_table.get(features))
  
      def add_alias(self, unicode alias, entities, probabilities):
          """For a given alias, add its potential entities and prior probabilies to the KB."""
        # Throw an error if the probabilities sum up to more than 1
        prob_sum = sum(probabilities)
        if prob_sum > 1:
            raise ValueError("The sum of prior probabilities for alias '" + alias + "' should not exceed 1, "
                                                                                    "but found " + str(prob_sum))

          cdef hash_t alias_hash = self.strings.add(alias)
  
          # Return if this alias was added before
          if alias_hash in self._alias_index:
              user_warning("Alias " + alias + " already exists in the KB")
              return
keep keep keep add keep keep keep keep keep keep
 check and unit test in case prior probs exceed 1 
spacy/kb.pyx