Error message

• Notice: Trying to get property 'value' of non-object in matelick_preprocess_page() (line 55 of themes/custom/matelick/matelick.theme).
• Notice: Trying to get property 'value' of non-object in matelick_preprocess_page() (line 56 of themes/custom/matelick/matelick.theme).
• Notice: Trying to get property 'value' of non-object in matelick_preprocess_page() (line 57 of themes/custom/matelick/matelick.theme).