loop though excel files do something and save them to new folder python pandas

I have am having trouble with a for loop. I dont know what happened, this used to work, but now it tells me "No objects to concatenate".

I want to accomplish two things. I want to loop through all excel files in a folder. For each excel file I want to remove 2 lines of header data (which the code below already does).

Then I want to save each edited file with its original file name in a new folder. But also, save a new file where all the data from each edited file is appended together.

I thought I had the append correct but for some reason it is not working anymore.

import os
import pandas as pd
import numpy as np

from pandas import Series, DataFrame

appended_data = []

path = 'C:TestTestRawFile'
for fn in os.listdir(path):
    if os.path.isfile(fn):
        # Import the excel file and call it xlsx_file
        xlsx_file = pd.ExcelFile(fn)
        # View the excel files sheet names
        xlsx_file.sheet_names
        # Load the xlsx files Data sheet as a dataframe
        df = xlsx_file.parse('Sheet1',header= None)
        df_NoHeader = df[2:]
        data = df_NoHeader
        appended_data.append(data)
appended_data = pd.concat(appended_data)

Here is the error I currently get.

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-46-962ccf280c0b> in <module>()
     11         data = df_NoHeader
     12         appended_data.append(data)
---> 13 appended_data = pd.concat(appended_data)

C:Anaconda2libsite-packagespandastoolsmerge.pyc in concat(objs, axis, join, join_axes, ignore_index, keys, levels, names, verify_integrity, copy)
    832                        keys=keys, levels=levels, names=names,
    833                        verify_integrity=verify_integrity,
--> 834                        copy=copy)
    835     return op.get_result()
    836 

C:Anaconda2libsite-packagespandastoolsmerge.pyc in __init__(self, objs, axis, join, join_axes, keys, levels, names, ignore_index, verify_integrity, copy)
    865 
    866         if len(objs) == 0:
--> 867             raise ValueError('No objects to concatenate')
    868 
    869         if keys is None:

ValueError: No objects to concatenate