"$ gem install therubyracer" Error Message

$ gem install therubyracer

ERROR:  Error installing therubyracer:
    ERROR: Failed to build gem native extension.
current directory:
C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/libv8-3.16.14.19/ext/libv8
C:/RailsInstaller/Ruby2.3.0/bin/ruby.exe -r ./siteconf20171029-15304-8yv6j.rb extconf.rb
creating Makefile

The system can not find the path specified.
C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/libv8-3.16.14.19/ext/libv8/builder.rb:86:in 'setup_python!': libv8 requires python 2 to be installed in order to build, but it is currently 3.4.1 (RuntimeError)
    from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/libv8-3.16.14.19/ext/libv8/builder.rb:53:in 'build_libv8!'
    from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/libv8-3.16.14.19/ext/libv8/location.rb:24:in 'install!'
    from extconf.rb:7:in '<main>'

extconf failed, exit code 1

Gem files will remain installed in C:\RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/libv8-3.16.14.19 for inspection.
Results logged to C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/extensions/x86-mingw32/2.3.0/libv8-3.16.14.19/gem_make.out
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...`