code: def _single_true(iterable):
      '''This returns True if only one True-ish element exists in `iterable`.
  
      Parameters
      ----------
  
      iterable : iterable
  
      Returns
      -------
  
      bool
          True if only one True-ish element exists in `iterable`. False otherwise.
  
      '''
  
      # return True if exactly one true found
      iterator = iter(iterable)
  
      # consume from "i" until first true or it's exhausted
      has_true = any(iterator)
  
      # carry on consuming until another true value / exhausted
      has_another_true = any(iterator)
  
      return has_true and not has_another_truf _single_true(iterable):
      '''This returns True if only one True-ish element exists in `iterable`.
  
      Parameters
      ----------
  
      iterable : iterable
  
      Returns
      -------
  
      bool
          True if only one True-ish element exists in `iterable`. False otherwise.
  
      '''
  
      # return True if exactly one true found
      iterator = iter(iterable)
  
      # consume from "i" until first true or it's exhausted
      has_true = any(iterator)
  
      # carry on consuming until another true value / exhausted
      has_another_true = any(iterator)
  
      return has_true and not has_another_true
docs: This returns True if only one True-ish element exists in `iterable`.
  
      Parameters
      ----------
  
      iterable : iterable
  
      Returns
      -------
  
      bool
          True if only one True-ish element exists in `iterable`. False otherwise.