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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 _get_flowcell_id(in_file, require_single=True):
 """Retrieve the unique flowcell id represented in the SampleSheet. """

    fc_ids = set([x[0] for x in _read_input_csv(in_file)])
    if require_single and len(fc_ids) > 1:
        raise ValueError("There are several FCIDs in the same samplesheet file: %s" % in_file)
    else:
        return fc_ids