Fix typo in bokeh.transform reference guide
@@ -53,7 +53,7 @@ __all__ = (
#-----------------------------------------------------------------------------
def cumsum(field, include_zero=False):
- ''' Create a Create a ``DataSpec`` dict to generate a ``CumSum`` expression
+ ''' Create a ``DataSpec`` dict to generate a ``CumSum`` expression
for a ``ColumnDataSource``.
Examples:
