Combine the list into a single string using the comma-separated-values convention.
Each entry of l will be converted to a string if it is not a string already.
If the entry contains the separator or a quote character, it will be delimited by quotes.
- Returns:
s - a string containing the entries of l combined using the comma-separated-values convention
- Arguments:
l - the list of entries to combine
sep - the string to use as a separator. A single comma character , will be used by default.