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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def process_file_sorted_by_pmid(file_name):
 """Processes a file and returns a dictionary mapping pmids to a list of statements corresponding to that pmid. Parameters file_name : str A csxml file to process Returns ------- s_dict : dict Dictionary mapping pmids to a list of statements corresponding to that pmid """

    s_dict = defaultdict(list)
    mp = process_file(file_name, lazy=True)

    for statement in mp.iter_statements():
        s_dict[statement.evidence[0].pmid].append(statement)
    return s_dict