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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 collect_data(parent_module):
 """ Find Picard VariantCallingMetrics reports and parse their data """


    data = dict()
    for file_meta in parent_module.find_log_files('picard/variant_calling_metrics', filehandles=True):
        s_name = None
        for header, value in table_in(file_meta['f'], pre_header_string='## METRICS CLASS'):
            if header == 'SAMPLE_ALIAS':
                s_name = value
                if s_name in data:
                    log.debug("Duplicate sample name found in {}! Overwriting: {}".format(file_meta['fn'], s_name))
                data[s_name] = OrderedDict()
            else:
                data[s_name][header] = value
    return data