def matches(charset)
      values.select {|v|
        v == charset || v == '*'
      }.sort {|a, b|
        # "*" gets least precedence, any others should be equal.
        a == '*' ? 1 : (b == '*' ? -1 : 0)
      }
    end
def matches(charset)
      values.select {|v|
        v == charset || v == '*'
      }.sort {|a, b|
        # "*" gets least precedence, any others should be equal.
        a == '*' ? 1 : (b == '*' ? -1 : 0)
      }
    end
Returns an array of character sets from this header that match the given
 +charset+, ordered by precedence.