module SubstringCounter

# File lib/substring_counter.rb, line 5
def count_occurances(*args)
        raise ArgumentError, "Requires at least one string argument" if args.length == 0
        unless args.all? { |arg| arg.instance_of? String }
                raise ArgumentError, "Must enter String arguments"
        end
        result = {}
        args.each { |keyword| result[keyword] = self.scan(keyword).count }
        args.length.eql?(1) ? result[args.first] : result
end