How to use the coveralls.handleInput function in coveralls

grunt.event.on('coverage', function(lcovFileContents, done) {
    // Set coverage config so karma-coverage knows to run coverage
    testConfig.coverage = true;
    require('coveralls').handleInput(lcovFileContents, function(err) {
      if (err) {
        return done(err);
      }
      done();
    });
  });

grunt.event.on('coverage', function (lcov, done) {
        require('coveralls').handleInput(lcov, function (err) {
            if (err) {
                return done(err);
            }
            done();
        });
    });

grunt.event.on('coverage', function (lcov, done) {
    require('coveralls').handleInput(lcov, function (error) {
      if (error && !(error instanceof Error)) {
        error = new Error(error)
      }

      done(error)
    })
  })

.on('end', function () {
    coveralls.handleInput(input, function (err) {
      if (err) {
        throw err;
      }
    });
  })
  .setEncoding('utf8');

fs.readFile(fileName, 'utf8', function(err, fileContent) {
          if (err) {
            grunt.log.error("Failed to read file '" + fileName + "', with error: " + err);
            return callback(false);
          }

          coveralls.handleInput(fileContent, function(err) {
            if (err) {
              grunt.log.error("Failed to submit '" + fileName + "' to coveralls: " + err);
              return callback(false);
            }

            grunt.verbose.ok("Successfully submitted " + fileName + " to coveralls");
            callback(true);
          });
        });
    }

grunt.event.on('coverage', function(lcov, done){
    require('coveralls').handleInput(lcov, function(err){
      if (err) {
        return done(err);
      }
      done();
    });
  });

grunt.event.on('coverage', function(lcov, done) {        
        require('coveralls').handleInput(lcov, function(err) {
            if (err) {
                return done(err);
            }
            done();
        });
    });

grunt.event.on('coverage', function(lcov, done){
        require('coveralls').handleInput(lcov, function(err){
            if (err) {
                return done(err);
            }
            done();
        });
    });