code: function isPackage(pkg) {
    return pkg.name && pkg.version && (pkg.dependencies || pkg.devDependencies)
  }
docs: /*
  
  if opts.override is non null, then resolve modules that match from there.
  
  {
  either pass in the package.json you want for that package.
  foo: foo_package_json
  
  or pass in another valid range...
  bar: {verison: '1.0.1', to: '~2.0.0'}
  this will replace any bar that can use 1.0.1 with something that matches ~2.0.0
  }