Where do the magic numbers (p, b1-b5) come from? Are these empirically found using curve fitting? Also, wouldn't it be better to write things like (+ (- (*

Where do the magic numbers (p, b1-b5) come from? Are these empirically found using curve fitting? Also, wouldn't it be better to write things like (+ (- (* (exp (* (- r) t)) strike) s) call))) in a more schemer-friendly way as (+ call (- s) (* strike (exp (- (* r t))))) to avoid parenthesis syndrome? (I was probably wrong to expect self-explanatory code, e.g. with docstrings, but IMO the readability could be improved)