Have the function mathChallenge $($str$)$take the str parameter,

which will be a simple mathematical formula with three numbers, a

single operator$(+,-,*,$or $/)$and an equal sign$(=)$and return the digit

that completes the equation. In one of the numbers in the equation,

there will be an x character, and your program should determine what digit

is missing. For example, if str is $"3$x$+12=46"$then your program should output $4.$

The x character can appear in any of the three numbers and all three numbers

will be greater than or equal to $0$and less than or equal to $1000000.$ Example: inputs : $"4-2=$x$"$output: $2$ need code in python