Macro Check-Type-Of-Arg

Part of:

package cl-mathstats
( check-type-of-arg < arg-name > < predicate > < type-string > &optional < error-type-name > )

Generate error if the value of ARG-NAME doesn't satisfy PREDICATE.
PREDICATE is a function name (a symbol) or an expression to compute.
TYPE-STRING is a string to use in the error message, such as “a list”.
ERROR-TYPE-NAME is a keyword that tells condition handlers what type was desired.