Python Issues

i appear to be having issues using anaconda.
i have copied the code into Jupyter note as follows:
In [1]:
def CryptoDataCSV(symbol, frequency):
​
#Params: String symbol, int frequency = 300,900,1800,7200,14400,86400
​
#Returns: df from first available date
​
url ='https://poloniex.com/public?command=returnChartData¤cyPair='+symbol+'&end=9999999999&period='+str(frequency)+'&start=0'
​
df = pd.read_json(url)
​
df.set_index('date',inplace=True)
​
df.to_csv(symbol + '.csv')
​
print('Processed: ' + symbol)
In [2]:
import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline
In [3]:
tickers = ['USDT_BTC','USDT_ETC','USDT_XMR','USDT_ETH','USDT_DASH',
'USDT_XRP','USDT_LTC','USDT_NXT','USDT_STR','USDT_REP','USDT_ZEC']
In [4]:
crypto_df = pd.DataFrame()
for ticker in tickers:
crypto_df[ticker] = pd.read_csv(ticker+'.csv', index_col = 'date')['close']
crypto_df.dropna(inplace=True)
---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
<ipython-input-4-b59f4116fa1a> in <module>()
      1 crypto_df = pd.DataFrame()
      2 for ticker in tickers:
----> 3     crypto_df[ticker] = pd.read_csv(ticker+'.csv', index_col = 'date')['close']
      4 crypto_df.dropna(inplace=True)
~\Anaconda3\lib\site-packages\pandas\io\parsers.py in parser_f(filepath_or_buffer, sep, delimiter, header, names, index_col, usecols, squeeze, prefix, mangle_dupe_cols, dtype, engine, converters, true_values, false_values, skipinitialspace, skiprows, nrows, na_values, keep_default_na, na_filter, verbose, skip_blank_lines, parse_dates, infer_datetime_format, keep_date_col, date_parser, dayfirst, iterator, chunksize, compression, thousands, decimal, lineterminator, quotechar, quoting, escapechar, comment, encoding, dialect, tupleize_cols, error_bad_lines, warn_bad_lines, skipfooter, skip_footer, doublequote, delim_whitespace, as_recarray, compact_ints, use_unsigned, low_memory, buffer_lines, memory_map, float_precision)
    653                     skip_blank_lines=skip_blank_lines)
    654
--> 655         return _read(filepath_or_buffer, kwds)
    656
    657     parser_f.__name__ = name
~\Anaconda3\lib\site-packages\pandas\io\parsers.py in _read(filepath_or_buffer, kwds)
    403
    404     # Create the parser.
--> 405     parser = TextFileReader(filepath_or_buffer, **kwds)
    406
    407     if chunksize or iterator:
~\Anaconda3\lib\site-packages\pandas\io\parsers.py in __init__(self, f, engine, **kwds)
    762             self.options['has_index_names'] = kwds['has_index_names']
    763
--> 764         self._make_engine(self.engine)
    765
    766     def close(self):
~\Anaconda3\lib\site-packages\pandas\io\parsers.py in _make_engine(self, engine)
    983     def _make_engine(self, engine='c'):
    984         if engine == 'c':
--> 985             self._engine = CParserWrapper(self.f, **self.options)
    986         else:
    987             if engine == 'python':
~\Anaconda3\lib\site-packages\pandas\io\parsers.py in __init__(self, src, **kwds)
   1603         kwds['allow_leading_cols'] = self.index_col is not False
   1604
-> 1605         self._reader = parsers.TextReader(src, **kwds)
   1606
   1607         # XXX
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader.__cinit__ (pandas\_libs\parsers.c:4209)()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._setup_parser_source (pandas\_libs\parsers.c:8873)()
FileNotFoundError: File b'USDT_BTC.csv' does not exist

I GET THE ABOVE ERROR. BASICALLY NOTHING HAPPENS!
i would appreciate help. My aim is to use this to download data for top 50 currencies to run in a forecasting and risk analysis model.