pandas Series object or DataFrame. None if absent.
int, size of batches to return.
int, number of epochs to iterate over data. If not None,
read attempts that would exceed this value will raise OutOfRangeError.
bool, whether to read the records in random order.
int, size of the read queue. If None, it will be set
roughly to the size of x.
Integer, number of threads used for reading and enqueueing. In
order to have predicted and repeatable order of reading and enqueueing,
such as in prediction and evaluation mode, num_threads should be 1.
str, name to give the target column y. This parameter
is not used when y is a DataFrame.
Function, that has signature of ()->(dict of features, target)
if x already contains a column with the same name as y, or
if the indexes of x and y don't match.