Added more constructor arguments

[Nyholm]

No description provided.

[cryptiklemur]

maybe:

if ($hasValue) {
    $this->value = $value;
}

[codecov-io]

Current coverage is 27.21%

Merging #4 into master will increase coverage by +1.16% as of 50d9fef

@@            master      #4   diff @@
======================================
  Files            2       2       
  Stmts          142     147     +5
  Branches         0       0       
  Methods         21      21       
======================================
+ Hit             37      40     +3
  Partial          0       0       
- Missed         105     107     +2

Review entire Coverage Diff as of 50d9fef

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