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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Update Cache Symbols
A useful utility for demonstating the use of the update/remove cache symbols functions.  You can use this notebook to periodically update all of the timeseries in your symbol cache.
Step1:  Update time series for the symbols below.
Time series will be fetched for any symbols not already cached.
Step2:  Remove the time series for TSLA
Step3:  Update time series for all symbols in the cache directory
Step4:  Remove time series for all symbols in the cache directory
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Python Code:
import pandas as pd
import pinkfish as pf
Explanation: Update Cache Symbols
A useful utility for demonstating the use of the update/remove cache symbols functions.  You can use this notebook to periodically update all of the timeseries in your symbol cache.
End of explanation
pf.update_cache_symbols(symbols=['msft', 'orcl', 'tsla'])
Explanation: Update time series for the symbols below.
Time series will be fetched for any symbols not already cached.
End of explanation
pf.remove_cache_symbols(symbols=['tsla'])
Explanation: Remove the time series for TSLA
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pf.update_cache_symbols()
Explanation: Update time series for all symbols in the cache directory
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# WARNING!!! - if you uncomment the line below, you'll wipe out
# all the symbols in your cache directory
#pf.remove_cache_symbols()
Explanation: Remove time series for all symbols in the cache directory
End of explanation
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