Drupal Coding Standards Issues | phpcs

Problem/Motivation

Getting following error/warnings

FILE: /app/modules/contrib/vbo_export/src/Plugin/Action/VboExportBase.php
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FOUND 4 ERRORS AND 1 WARNING AFFECTING 5 LINES
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114 | ERROR | [x] Use null coalesce operator instead of ternary operator.
120 | ERROR | [x] Use null coalesce operator instead of ternary operator.
150 | ERROR | [x] Use null coalesce operator instead of ternary operator.
156 | ERROR | [x] Use null coalesce operator instead of ternary operator.
200 | WARNING | [ ] Unused variable $rand.
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PHPCBF CAN FIX THE 4 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: /app/modules/contrib/vbo_export/src/Plugin/Action/VboExportCsv.php
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FOUND 1 ERROR AFFECTING 1 LINE
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35 | ERROR | [x] Use null coalesce operator instead of ternary operator.
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PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
--------------------------------------------------------------------------

FILE: /app/modules/contrib/vbo_export/src/Plugin/Action/VboExportPdf.php
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FOUND 4 ERRORS AFFECTING 4 LINES
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15 | ERROR | [x] There must be one blank line after the last USE statement; 0 found;
31 | ERROR | [ ] Missing @var tag in member variable comment
81 | ERROR | [x] Use null coalesce operator instead of ternary operator.
90 | ERROR | [x] Use null coalesce operator instead of ternary operator.
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PHPCBF CAN FIX THE 3 MARKED SNIFF VIOLATIONS AUTOMATICALLY
--------------------------------------------------------------------------------------

FILE: /app/modules/contrib/vbo_export/src/Plugin/Action/VboExportXlsx.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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65 | WARNING | t() calls should be avoided in classes, use \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
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Time: 4.47 secs; Memory: 12MB

Steps to reproduce

Run following command

phpcs --standard="Drupal,DrupalPractice" --extensions=php,module,inc,install,test,profile,theme,css,info,txt,md,yml modules/contrib/vbo_export/

Proposed resolution

Above error/warnings need to be fixed