code: def buildTreeFromAlignment(filename,WorkingDir=None,SuppressStderr=None):
      
      app = Clustalw({'-tree':None,'-infile':filename},SuppressStderr=\
          SuppressStderr,WorkingDir=WorkingDir)
      app.Parameters['-align'].off()
      return app()
docs: Builds a new tree from an existing alignment
  
      filename: string, name of file containing the seqs or alignment