Fixed docstring in diff_tables() (Issue #182)

data_diff/diff_tables.py

@@ -311,8 +311,8 @@ def diff_tables(self, table1: TableSegment, table2: TableSegment) -> DiffResult:
 
  Returns:
  An iterator that yield pair-tuples, representing the diff. Items can be either
- ('+', columns) for items in table1 but not in table2
- ('-', columns) for items in table2 but not in table1
+ ('-', columns) for items in table1 but not in table2
+ ('+', columns) for items in table2 but not in table1
  Where `columns` is a tuple of values for the involved columns, i.e. (id, ...extra)
  """
  # Validate options