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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def GetUsernameForPath(self, path):
 """Retrieves a username for a specific path. This is determining if a specific path is within a user's directory and returning the username of the user if so. Args: path (str):
 path. Returns: str: username or None if the path does not appear to be within a user's directory. """

    path = path.lower()

    user_accounts = self._user_accounts.get(self.CURRENT_SESSION, {})
    for user_account in iter(user_accounts.values()):
      if not user_account.user_directory:
        continue

      user_directory = user_account.user_directory.lower()
      if path.startswith(user_directory):
        return user_account.username

    return None