how do i fix this php error?
Fatal error: Call to a member function hooks_dp3rsSidebar() on a non-object in
on line 63
and this is what on line 63:

return $this->registry->output->getTemplate( 'referrals' )->hooks_dp3rsSidebar( $this->referralsSystemLibrary->getTopXReferrers() );
how do i fix this php error?
===

Fatal error: Call to a member function hooks_dp3rsSidebar() on a non-object in
on line 63
and this is what on line 63:

return $this->registry->output->getTemplate( 'referrals' )->hooks_dp3rsSidebar( $this->referralsSystemLibrary->getTopXReferrers() );