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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_num_sequenced(study_id):
 """Return number of sequenced tumors for given study. This is useful for calculating mutation statistics in terms of the prevalence of certain mutations within a type of cancer. Parameters study_id : str The ID of the cBio study. Example: 'paad_icgc' Returns ------- num_case : int The number of sequenced tumors in the given study """

    data = {'cmd': 'getCaseLists',
            'cancer_study_id': study_id}
    df = send_request(**data)
    if df.empty:
        return 0
    row_filter = df['case_list_id'].str.contains('sequenced', case=False)
    num_case = len(df[row_filter]['case_ids'].tolist()[0].split(' '))
    return num_case