def to_s( pattern="" )
      return '' if self.empty?
      to_return = pattern.is_a?( Symbol ) ? @@patterns[pattern] : pattern
      to_return = @@patterns[:us_short] if to_return.empty?
      @pattern_map.each { |pat, replacement| to_return = to_return.gsub( pat, replacement ) }
      to_return.strip
    end
def to_s( pattern="" )
      return '' if self.empty?
      to_return = pattern.is_a?( Symbol ) ? @@patterns[pattern] : pattern
      to_return = @@patterns[:us_short] if to_return.empty?
      @pattern_map.each { |pat, replacement| to_return = to_return.gsub( pat, replacement ) }
      to_return.strip
    end
Creates a phone number based on pattern provided.  Defaults to US (NANP) formatting (111) 111-1111.

 Symbols:
   %c - country code
   %a - area code
   %m - subscriber prefix
   %p - subscriber postfix