def add_roman_scheme(name, scheme)
      name = name.to_sym
      scheme = scheme.deep_dup
      scheme[:vowel_marks] = scheme[:vowels][1..-1] unless scheme.key?(:vowel_marks)
      @schemes[name] = IceNine.deep_freeze(scheme)
      @roman_schemes.add(name)
      @scheme_names.add(name)
      scheme
    end
def add_roman_scheme(name, scheme)
      name = name.to_sym
      scheme = scheme.deep_dup
      scheme[:vowel_marks] = scheme[:vowels][1..-1] unless scheme.key?(:vowel_marks)
      @schemes[name] = IceNine.deep_freeze(scheme)
      @roman_schemes.add(name)
      @scheme_names.add(name)
      scheme
    end
Add a roman scheme to Sanscript.

 @param name [Symbol] the scheme name
 @param scheme [Hash] the scheme data, constructed as in {add_brahmic_scheme}.
                      The "vowel_marks" field can be omitted
 @return [Hash] the frozen scheme data as it exists inside the module