How to make reference to text output file from "Flat File Document Parser" by Python Node

Please help.

I am new to KNIME and Python, I would like to make use of the output from "Flat File Document Parser" node by "Python Script (1=>1)" node for subsequent processing.

Objectives:  I don't how to access various text files from "Flat File Document Parser" with "Python Script (1=>1)". 

Here is the workflow details: "Flat File Document Parser" Node connected to "Python Script (1=>1)" Node

"Flat File Document Parser" Node refers to a folder with several text documents

"Python Script (1=>1)" Node, which consists of only a column named "Document".  I would like to read the document content by the following script:

import re, sys
y=input_table['Document']  """Document is the column in Python Script (1=>1)"""
text1=''.join(str(x) for x in y)
f = open(text1,'r')


However, the print(text1) only generate the file names, not the content of the text files.

The following errors was displayed as follows:

Traceback (most recent call last):
  File "C:\Program Files\KNIME\plugins\org.knime.python_3.3.0.v201611242050\py\", line 282, in execute
    exec(source_code, _exec_env, _exec_env)
  File "<string>", line 5, in <module>
IOError: [Errno 22] invalid mode ('r') or filename: ...

Appreciated if you could help on this.

Double post, please see here: