How do I properly write scipy.stats.binom.cdf() details
&gt;&gt;&gt; from scipy.stats import binom
&gt;&gt;&gt; binom.cdf(0, 10000,10/19)
0.0


Binomial random variable are nonnegative. Hence you want to compute the probability that it is equal to zero which is 

$$\left(\frac{10}{19} \right)^{10000}\approx 10^{-2787.54}\approx 0$$