public function fromBase(string $number, int $base) : string
    {
        return $this->fromArbitraryBase(\strtolower($number), self::ALPHABET, $base);
    }
public function fromBase(string $number, int $base) : string
    {
        return $this->fromArbitraryBase(\strtolower($number), self::ALPHABET, $base);
    }
public function fromBase ( string $ number , int $ base ) : string { return $ this -> fromArbitraryBase ( \ strtolower ( $ number ) , self :: ALPHABET , $ base ) ; }
Converts a number from an arbitrary base.

This method can be overridden by the concrete implementation if the underlying library
has built-in support for base conversion.

@param string $number The number, positive or zero, non-empty, case-insensitively validated for the given base.
@param int    $base   The base of the number, validated from 2 to 36.

@return string The converted number, following the Calculator conventions.
Converts a number from an arbitrary base .