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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 _fill_mi_header(row, control_row):
 """Forward fill blank entries in row but only inside the same parent index. Used for creating headers in Multiindex. Parameters row : list List of items in a single row. control_row : list of bool Helps to determine if particular column is in same parent index as the previous value. Used to stop propagation of empty cells between different indexes. Returns Returns changed row and control_row """

    last = row[0]
    for i in range(1, len(row)):
        if not control_row[i]:
            last = row[i]

        if row[i] == '' or row[i] is None:
            row[i] = last
        else:
            control_row[i] = False
            last = row[i]

    return row, control_row