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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 read_hector_constraint(constraint_file):
 """ Reads a Hector contraint CSV file and returns it as a Pandas Series """

    df = pd.read_csv(constraint_file, index_col=0, comment=";")
    df = df[df.applymap(lambda x: isinstance(x, (int, float)))]
    df.index = df.index.astype(int)
    return df.iloc[:, 0]