How to check if a string is a valid md5 hash

<?php
function MD5_Hashed_is_Valid($md5)
{
      return !empty($md5) && preg_match('/^[a-f0-9]{32}$/', $md5);
}

$MD5_Hashed = "e10adc3949ba59abbe56e057f20f883e";
if(MD5_Hashed_is_Valid($MD5_Hashed))
{
      echo "Your given MD5 Hashed string is valid.";
}
else
{
      echo "Sorry, your given MD5 Hashed string is not valid.";
}
?>