if (my $sth = $self->{$dbh}{$query}) {                                                                                              
    warn "Using cached statement handler\n" if $self->debug;                                                                          
    return $sth;                                                                                                                      
  } else {                                                                                                                            
    warn "Creating new statement handler\n" if $self->debug;                                                                          
    $sth = $dbh->prepare($query) || $self->throw("Couldn't prepare query $query:\n ".DBI->errstr."\n");                               
    return $self->{$dbh}{$query} = $sth;                                                                                              
  }