<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def jarsign(storepass, keypass, keystore, source, alias, path=None):
 """ Uses Jarsign to sign an apk target file using the provided keystore information. :param storepass(str) - keystore storepass :param keypass(str) - keystore keypass :param keystore(str) - keystore file path :param source(str) - apk path :param alias(str) - keystore alias :param path(str) - basedir to run the command """

  cmd = [
    'jarsigner',
    '-verbose',
    '-storepass',
    storepass,
    '-keypass',
    keypass,
    '-keystore',
    keystore,
    source,
    alias
  ]
  common.run_cmd(cmd, log='jarsign.log', cwd=path)