isAbstract() public method

Is this class an abstract class.
public isAbstract ( ) : boolean
return boolean
 function it_might_be_abstract(ReflectionClass $reflectionClass)
 {
     $reflectionClass->isAbstract()->willReturn(false);
     $this->isAbstract()->shouldBe(false);
     $reflectionClass->isAbstract()->willReturn(true);
     $this->isAbstract()->shouldBe(true);
 }
 /**
  * {@inheritDoc}
  */
 public function isAbstract()
 {
     return $this->betterReflectionClass->isAbstract();
 }
 public function isAbstract() : bool
 {
     return $this->reflectionClass->isAbstract();
 }