Truncate series to the given degree.
Reduce the degree of the series to deg by discarding the high order terms. If deg is greater than the current degree a copy of the current series is returned. This can be useful in least squares where the coefficients of the high degree terms may be very small.
New in version 1.5.0.
deg : non-negative int
The series is reduced to degree deg by discarding the high order terms. The value of deg must be a non-negative integer.
new_series : series
New instance of series with reduced degree.