def include_char?(char)
      unless char.empty?
        @chars.has_value?(char) || include_byte?(char_to_byte(char))
      else
        false
      end
    end
def include_char?(char)
      unless char.empty?
        @chars.has_value?(char) || include_byte?(char_to_byte(char))
      else
        false
      end
    end
Determines if a character is contained within the character set.

 @param [String] char
   The character to search for.

 @return [Boolean]
   Specifies whether the character is contained within the
   character set.