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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:
 Fixed-Point Iteration
The function fixpoint takes two arguments
Step1:  The function fixpoint2 takes two arguments
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Python Code:
def fixpoint(S0, f):
    Result = S0.copy() # don't change S0
    while True:
        NewElements = { x for o in Result 
                          for x in f(o) 
                      }
        if NewElements.issubset(Result):
            return Result
        Result |= NewElements
Explanation: Fixed-Point Iteration
The function fixpoint takes two arguments:
  - $S_0$ is a set of elements, 
  - $f$ is a function mapping elements to sets of elements.  
The function fixpoint computes the smallest set $S$ such the following conditions holds: 
- $S_0 \subseteq S$,
- $S = \bigcup { f(x) \mid x \in S }$.
End of explanation
def fixpoint2(S0, f):
    Result = S0.copy() # don't change S0
    while True:
        NewElements = f(Result)
        if NewElements.issubset(Result):
            return Result
        Result |= NewElements
Explanation: The function fixpoint2 takes two arguments:
  - $S_0$ is a set of elements, 
  - $f$ is a function mapping sets of elements to sets of elements.  
The function fixpoint2 computes the smallest set $S$ such the following conditions holds: 
- $S_0 \subseteq S$,
- $S = f(S)$.
End of explanation
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