Cleans the column names on a DataFrame
    Parameters:
    df - DataFrame
        The DataFrame to clean

def clean_colnames(df):
    """ Cleans the column names on a DataFrame
    Parameters:
    df - DataFrame
        The DataFrame to clean
    """
    col_list = []
    for index in range(_dutils.cols(df)):
        col_list.append(df.columns[index].strip().lower().replace(' ','_'))
    df.columns = col_list