code: def insert_inexistence(self, table, kwargs, condition):
          
          sql = "insert into " + table + " ({}) "
          select = "select {} "
          condition = "where not exists (select 1 from " + table + "{} limit 1);".format( self.parse_condition(condition) )
          keys, values = [], []
          [ (keys.append(k), values.append(v)) for k, v in kwargs.iteritems() ]
          sql = sql.format(', '.join(keys)) + select.format( ', '.join(['%s']*len(values)) ) + condition
          super(PGWrapper, self).execute(sql, values, result=False)
docs: .. :py:method::
  
          Usage::
  
              >>> insert('hospital', {'id': '12de3wrv', 'province': 'shanghai'}, {'id': '12de3wrv'})
              insert into hospital (id, province) select '12de3wrv', 'shanghai' where not exists (select 1 from hospital where id='12de3wrv' limit 1);