hello, I need help solving this computer science question.

Let = {0, 1, 2}. For a string w with alphabet , the aab-fication of w is defined by replacing every 0 by the string aab, every 1 by the string a and every 2 by the string ab. For a language L whose alphabet is , the aab-fication of L is obtained by taking the aab-fication of every string in L. For example, if 012 is in L, then aabaab is in the aab-fication of L. Prove that the regular languages are closed under aab-fication.