Using PHP, design a function that given a Roman numeral (Links to an external site.)Links to an external site. in input, is able to compute the modern HinduArabic numeral (Links to an external site.)Links to an external site. system representation (aka, 0123456789).

For example:

Input	Output
VI	6
IV	4
MCMXC	1990
IX	9

• Be sure to add all the necessary checks and at least one testing function.
• Try to split the logic in more small functions.