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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 compute_indel_length(fs_df):
 """Computes the indel length accounting for wether it is an insertion or deletion. Parameters fs_df : pd.DataFrame mutation input as dataframe only containing indel mutations Returns ------- indel_len : pd.Series length of indels """

    indel_len = pd.Series(index=fs_df.index)
    indel_len[fs_df['Reference_Allele']=='-'] = fs_df['Tumor_Allele'][fs_df['Reference_Allele']=='-'].str.len()
    indel_len[fs_df['Tumor_Allele']=='-'] = fs_df['Reference_Allele'][fs_df['Tumor_Allele']=='-'].str.len()
    indel_len = indel_len.fillna(0).astype(int)
    return indel_len