public function isNegative(): bool
    {
        if ($this->number === 0 ){
            throw new IsZeroException('0 is neither positive or negative');
        }
        return (!is_int($this->number) && $this->number < 0 || $this->number < 0);
    }
public function isNegative(): bool
    {
        if ($this->number === 0 ){
            throw new IsZeroException('0 is neither positive or negative');
        }
        return (!is_int($this->number) && $this->number < 0 || $this->number < 0);
    }
public function isNegative ( ) : bool { if ( $ this -> number === 0 ) { throw new IsZeroException ( '0 is neither positive or negative' ) ; } return ( ! is_int ( $ this -> number ) && $ this -> number < 0 || $ this -> number < 0 ) ; }
Is the number negative

@return bool
@throws IsZeroException
Is the number negative