Write a script that converts between US dollars and Euros. $($Use a rate of $1$ US $=0\mathrm{.}7$ E for this exercise.$)$ The script should take one numerical required argument and one optional argument $($the currency, E or US$).$ If the user gives two arguments, perform the conversion. If the user gives only one argument, a number, assume the number is given in US dollars, warn the user, and perform the conversion. If the user gives no arguments, print a statement explaining how to run it$.$ Examples of test cases and resulting output are shown below: Input Output $45\mathrm{.}32$ E $45\mathrm{.}32$ Euros is equivalent to $64\mathrm{.}74$ US Dollars $55$ Since you didn$$t specify a currency, I$$m assuming US to Euros. $55$ US Dollars is equivalent to $38\mathrm{.}5$ Euros $100$ US $100\mathrm{.}00$ US Dollars is equivalent to $70\mathrm{.}00$ Euros $($No arguments$)$ Usage: number $\{$currency $($US or E$)\}$ Example: $100$ US