Why does drupal swear at the output of variables in the template?

Question

Drupal

Installed the Print Email and PDF module.
I display in the actually created print.tpl.php file (in the theme folder) the node fields with the following code:

<?php print $node->field_estate_type[LANGUAGE_NONE][0]['taxonomy_term']->name; ?>

But cms starts to display errors like: Undefined index: taxonomy_term in the include() function in the print.tpl.php file exactly on this line in the include() function.
What is the reason for the error? Am I displaying the fields incorrectly? Thank you.

Answer 1

https://habrahabr.ru/post/163501/
this article will probably help me.

Answer 2

install the Devel module and write the code:
<?php dpm($node->field_estate_type[LANGUAGE_NONE][0]); ?>
to see what elements are in this array. perhaps there is no taxonomy_term element