def check_cpusubtype(cputype, cpusubtype)
      # Only check sub-type w/o capability bits (see `populate_mach_header`).
      raise CPUSubtypeError.new(cputype, cpusubtype) unless Headers::CPU_SUBTYPES[cputype].key?(cpusubtype)
    end
def check_cpusubtype(cputype, cpusubtype)
      # Only check sub-type w/o capability bits (see `populate_mach_header`).
      raise CPUSubtypeError.new(cputype, cpusubtype) unless Headers::CPU_SUBTYPES[cputype].key?(cpusubtype)
    end
Check the file's CPU type/subtype pair.
 @param cpusubtype [Integer] the CPU subtype
 @raise [CPUSubtypeError] if the CPU sub-type is unknown
 @api private