Consider the language L$1,$ where #$1($x$)$ means the number of occurrences of $1$ in x$.$ L$1$ contains string such as $,011,010111,$ and $110110101011.$ L$1=\{$ x : #$1($x$)=2*$ #$0($x$)\}.($b$)$ Write down al the steps of a Pumping Lemma proof showing that L$1$ is not regular $($i$)$ What is an initial parametric string you would choose and why?