# File lib/math_ml/util.rb, line 31
        def self.collect_regexp(a)
                if a
                        a = [a].flatten
                        a.size>0 ? Regexp.new(a.inject(""){|r, i| i.is_a?(Regexp) ? "#{r}#{i.to_s}|" : r}.chop) : INVALID_RE
                else
                        INVALID_RE
                end
        end