code: function validateSourcePath(sourcePath) {
      const materialPackageJSONPath = pathUtils.resolve(sourcePath, 'package.json');
  
      return fs.readFileAsync(materialPackageJSONPath, { encoding: 'UTF8' })
          .then(materialPackageJSONString => {
              const package = JSON.parse(materialPackageJSONString);
              if (package.name !== sourcePackageName) {
                  throw new Error(`Source path ${sourcePath} does not appear to be a clone of https://github.com/callemall/material-ui`);
              }
              return sourcePath;
          });
  }
docs: Make sure the source path is correct in that it exists and appears to point to the root of the repo we want.