def set_delimited_file_column_names(self, column_names):
self.delimited_file_column_names = column_names<EOL>
takes a list of column_names 
when column names are provided, then if number of 
column names matches the number of columns when
lines are split on delimiter, load returns
a list of dictionaries such that the keys are
the column names. 
when column names are not provided or number of
column names doesn't match number of columns,
load returns a list of tuples.