Here's an example definition of the function diabetes_test_statistic:
```
import numpy as np
def diabetes_test_statistic(sample, proportions):
# Calculate the observed prevalence of diabetes in the sample
observed_prevalence = np.mean(sample)
# Simulate a new sample from the null hypothesis
null_sample = np.random.choice([0, 1], size=len(sample), p=proportions)
# Calculate the prevalence of diabetes in the null sample
null_prevalence = np.mean(null_sample)
# Calculate the absolute difference between the observed and null prevalences
test_statistic = np.abs(observed_prevalence - null_prevalence)
return test_statistic
```
This function takes two arguments: `sample`, which is the original sample of patients, and `proportions`, which is an array containing the true population proportions of patients without and with diabetes. The function first calculates the observed prevalence of diabetes in the sample by taking the mean of the values in the sample array. It then simulates a new sample from the null hypothesis by randomly sampling from the two proportions in the `proportions` array. It calculates the prevalence of diabetes in the null sample and then calculates the absolute difference between the observed and null prevalences. Finally, it returns the test statistic, which is the absolute difference between the observed and null prevalences.