code: def earliest_possible_date():
      """
      The earliest date for which we can load data from this module.
      """
      # The US Treasury actually has data going back further than this, but it's
      # pretty rare to find pricing data going back that far, and there's no
      # reason to make people download benchmarks back to 1950 that they'll never
      # be able to use.
      return pd.Timestamp("1980", tz="UTC")
  
file_path: catalyst/catalyst/data/treasuries.py
imports: from operator import itemgetter
  import re
  import numpy
  import pandas
label_desc: Use image node_id 2 for calling a global function with example usage: earliest_possible_date() and returns: pd