class_docstr: A strategy which always returns a single fixed value.
  
  It's implemented as a length-one SampledFromStrategy so that all our
  special-case logic for filtering and sets applies also to just(x).
  
  The important difference from a SampledFromStrategy with only one
  element to choose is that JustStrategy *never* touches the underlying
  choice sequence, i.e. drawing neither reads from nor writes to `data`.
  This is a reasonably important optimisation (or semantic distinction!)
  for both JustStrategy and SampledFromStrategy.
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code: def calc_is_cacheable(self, recur):
      return is_simple_data(self.value)
  
imports: from hypothesis.internal.reflection import get_pretty_function_description
  from hypothesis.strategies._internal.strategies import SampledFromStrategy, SearchStrategy, T, is_simple_data
  from hypothesis.strategies._internal.utils import cacheable, defines_strategy
label_desc: Use image node_id 3 for calling the JustStrategy obj's underlying member method code with example usage: obj.calc_is_cacheable(recur) and returns: is_simple_data