{"text_format":"3","workbook":"xls","n_sheets":1,"sheets":["customers"],"read":"whole","date_system":"1900","formulas":"cached_only"}

{"sheet":"customers","index":0,"n_rows":4,"n_cols":7,"rows_kept":4,"flags":["formulas_cached_only"]}
["email","customer_group_code","first_name","last_name","phone","date_of_birth","gender"]
["john@example.com","wholesale","John","Doe",null,"1991-05-15","Male"]
["jane@example.com","general","Jane","Smith",null,"1991-05-15","Female"]
["robert@example.com","general","Robert","Johnson",null,"1990-11-26","Male"]