original_string: public function setVerticalBorderChars(string $outside, string $inside = null): self
      {
          $this->verticalOutsideBorderChar = $outside;
          $this->verticalInsideBorderChar = $inside ?? $outside;
  
          return $this;
      }
code: public function setVerticalBorderChars(string $outside, string $inside = null): self
      {
          $this->verticalOutsideBorderChar = $outside;
          $this->verticalInsideBorderChar = $inside ?? $outside;
  
          return $this;
      }
code_tokens: public function setVerticalBorderChars ( string $ outside , string $ inside = null ) : self { $ this -> verticalOutsideBorderChar = $ outside ; $ this -> verticalInsideBorderChar = $ inside ?? $ outside ; return $ this ; }
docstring: Sets vertical border characters.
  
  <code>
  ╔═══════════════╤══════════════════════════╤══════════════════╗
  ║ ISBN          │ Title                    │ Author           ║
  ╠═══════1═══════╪══════════════════════════╪══════════════════╣
  ║ 99921-58-10-7 │ Divine Comedy            │ Dante Alighieri  ║
  ║ 9971-5-0210-0 │ A Tale of Two Cities     │ Charles Dickens  ║
  ╟───────2───────┼──────────────────────────┼──────────────────╢
  ║ 960-425-059-0 │ The Lord of the Rings    │ J. R. R. Tolkien ║
  ║ 80-902734-1-6 │ And Then There Were None │ Agatha Christie  ║
  ╚═══════════════╧══════════════════════════╧══════════════════╝
  </code>
  
  @param string      $outside Outside border char (see #1 of example)
  @param string|null $inside  Inside border char (see #2 of example), equals $outside if null
docstring_tokens: Sets vertical border characters .