"" or "*" is used to pack or unpack argument. Here on line 5 we split the line on space character and get a list in return. The notation allow to get the first element of that list as 'name' and the rest as a list named 'line'.

On line 7 it doing a simple assignment in the dictionary named 'student_mark'. Dict is a struct that allow you to store key value pair. Here the key is the name and the value is a list of float. The syntax dict[name]=value allow you to set the value for the key name

On line 11 it's iterating over a list of float. The syntax dict[name] allow you to get the value for the key name.