I want to add all the data from charts.zip from https://doi.org/10.5281/zenodo.4778562 in a single DataFrame. The data consist of a file per year that contains multiple CSVs. I made the following code:
header = 0
dfs = []
for file in glob.glob('Charts/*/201?/*.csv'):
    region = file.split('/')[1]
    dates = re.findall('\d{4}-\d{2}-\d{2}', file.split('/')[-1])
    weekly_chart = pd.read_csv(file, header=header, sep='\t')
    weekly_chart['week_start'] = datetime.strptime(dates[0], '%Y-%m-%d')
    weekly_chart['week_end'] = datetime.strptime(dates[1], '%Y-%m-%d')
    weekly_chart['region'] = region
    dfs.append(weekly_chart)
all_charts = pd.concat(dfs)
But, when I run it, python returns:
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/tmp/ipykernel_12886/3473678833.py in <module>
      9     weekly_chart['region'] = region
     10     dfs.append(weekly_chart)
---> 11 all_charts = pd.concat(dfs)
~/Downloads/enter/lib/python3.9/site-packages/pandas/util/_decorators.py in wrapper(*args, **kwargs)
    309                     stacklevel=stacklevel,
    310                 )
--> 311             return func(*args, **kwargs)
    312 
    313         return wrapper
~/Downloads/enter/lib/python3.9/site-packages/pandas/core/reshape/concat.py in concat(objs, axis, join, ignore_index, keys, levels, names, verify_integrity, sort, copy)
    344     ValueError: Indexes have overlapping values: ['a']
    345     """
--> 346     op = _Concatenator(
    347         objs,
    348         axis=axis,
~/Downloads/enter/lib/python3.9/site-packages/pandas/core/reshape/concat.py in __init__(self, objs, axis, join, keys, levels, names, ignore_index, verify_integrity, copy, sort)
    401 
    402         if len(objs) == 0:
--> 403             raise ValueError("No objects to concatenate")
    404 
    405         if keys is None:
ValueError: No objects to concatenate
How can I fix it?