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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 check_event_coverage(patterns, event_list):
 """Calculate the ratio of patterns that were extracted."""

    proportions = []
    for pattern_list in patterns:
        proportion = 0
        for pattern in pattern_list:
            for node in pattern.nodes():
                if node in event_list:
                    proportion += 1.0 / len(pattern_list)
                    break
        proportions.append(proportion)
    return proportions