What is the test for constitutional validity of a criminal statute when the statute is too vague?

United States v. Batchelder (1979) 442 U.S. 114, 123, 99 S.Ct. 2198, 60 L.Ed.2d 755.) However, " [i]t is impossible, given the complexities of our language and the variability of human conduct, to achieve perfect clarity in criminal statutes. Reasonable specificity exists if the statutory language "conveys sufficiently definite warning as to the proscribed conduct when measured by common understandings and practices." [Citations.] [Citation.] "[S]tatutes are not automatically invalidated as impermissibly vague simply because difficulty is found in determining whether certain marginal offenses fall within their language. [Citation.]" [Citation.] [Citation.]" ( People v. Hagedorn (2005) 127 Cal.App.4th 734, 746, 25 Cal.Rptr.3d 879.) " All presumptions and intendments favor the validity of a statute and mere doubt does not afford sufficient reason for a judicial declaration of invalidity. Statutes must be upheld unless their unconstitutionality clearly, positively and unmistakably appears. [Citation.]" ( People v. Garcia (2014) 230 Cal.App.4th 763, 768, 178 Cal.Rptr.3d 883.)