Error message

• Notice: Undefined offset: 0 in tecnosens_preprocess_node() (line 138 of themes/custom/tecnosens/tecnosens.theme).
• Notice: Trying to get property 'alias' of non-object in tecnosens_preprocess_node() (line 138 of themes/custom/tecnosens/tecnosens.theme).
• Notice: Undefined offset: 0 in tecnosens_preprocess_node() (line 138 of themes/custom/tecnosens/tecnosens.theme).
• Notice: Trying to get property 'alias' of non-object in tecnosens_preprocess_node() (line 138 of themes/custom/tecnosens/tecnosens.theme).