code: def open(self):
          
          if self._table_exists():
              self.mode = "open"
              # get table info
              self._get_table_info()
              self.types = dict([ (f[0],self.conv_func[f[1].upper()]) 
                  for f in self.fields if f[1].upper() in self.conv_func ])
              return self
          else:
              # table not found
              raise IOError,"Table %s doesn't exist" %self.name
docs: Open an existing database