Use existing classes for the covariance example
Use existing classes for the covariance example

rtoal/polyglot,rtoal/ple,rtoal/polyglot,rtoal/ple,rtoal/ple,rtoal/polyglot,rtoal/polyglot,rtoal/polyglot,rtoal/ple,rtoal/polyglot,rtoal/ple,rtoal/polyglot,rtoal/polyglot,rtoal/polyglot,rtoal/polyglot,rtoal/polyglot,rtoal/ple,rtoal/ple,rtoal/ple,rtoal/ple,rtoal/ple,rtoal/polyglot,rtoal/ple,rtoal/polyglot,rtoal/ple,rtoal/ple,rtoal/polyglot,rtoal/ple,rtoal/ple,rtoal/polyglot,rtoal/ple