Workplace chat software maker Slack Technologies continued its fervent pace of fundraising with a $427 million round of investment. The deal, led by private equity firms Dragoneer Investment Group and General Atlantic, values the business at about $7.1 billion, the San Francisco-based company said on Tuesday.Just under a year ago, an investment from SoftBank Group Corp. valued Slack at $5 billion. The latest deal brings Slack's total funds raised to $1.27 billion.