Consider a programming language that has comments as follows:

$-$ comments start with a line beginning with three consecutive equal signs, $===,$ followed by

any characters until the end of the line $($and a newline $$

$$ at the end$)$

$-$ comments end with a line consisting of equal signs only, at least three $($and a newline $$

$$ at

the end$)$

Example of a comment $($newlines are shown for clarity$)$:

$=======$ this is a comment $=======$

$***$ some stuff $***$

$================$

Write a regular expression that describes precisely the above described comments. You can use the

notation $\backslash$Sigma $\{$a$\}$ to describe the set of all characters different from a$.$