coef is a Method which extracts model coefficients
from objects returned by the stergm function.
coefficients is an alias for it.## S3 method for class 'stergm':
coef(object, \dots)
## S3 method for class 'stergm':
coefficients(object, \dots)stergm fit.object in the form of a list with
two elements: stergm and ergm