conan入门(十五):AttributeError: ‘CMake‘ object has no attribute ‘definitions‘

from conans import ConanFile
from conan.tools.cmake import CMakeToolchain, CMake
from conan.tools.layout import cmake_layout


class Bin2cConan(ConanFile):
    name = "bin2c"
    version = "1.0.0"

    # Optional metadata
    license = "BSD-2-Clause"
    author = "gwilymk 10km"
    url = "https://gitee.com/l0km/bin2c"
    description = "A simple utility for converting a binary file to a c application which can then be included within an application."
    topics = ("bin")

    # Binary configuration
    settings = "os", "compiler", "build_type", "arch"

    # Sources are located in the same place as this recipe, copy them to the recipe
    exports_sources = "CMakeLists.txt", "src/*"

    def layout(self):
        cmake_layout(self)

    def generate(self):
        tc = CMakeToolchain(self)
        tc.generate()

    def build(self):
        cmake = CMake(self)
        cmake.configure()
        cmake.build()

    def package(self):
        cmake = CMake(self)
        cmake.install()

    def configure(self):
        del self.settings.compiler.libcxx
        del self.settings.compiler.cppstd

    def build(self):
        cmake = CMake(self)
        cmake.configure()
        cmake.definitions["USE_BZ2"] = False
        cmake.build()

$ conan create .
Exporting package recipe
bin2c/1.0.0 exports_sources: Copied 1 '.txt' file: CMakeLists.txt
bin2c/1.0.0 exports_sources: Copied 1 '.c' file: bin2c.c
bin2c/1.0.0: The stored package has not changed
bin2c/1.0.0: Exported revision: b6fb6e6ab5a27e021f31f7048ca1ea66
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=14
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

bin2c/1.0.0: Forced build from source
bin2c/1.0.0 (test package): Installing package
Requirements
    bin2c/1.0.0 from local cache - Cache
Packages
    bin2c/1.0.0:63da998e3642b50bee33f4449826b2d623661505 - Build

Installing (downloading, building) binaries...
bin2c/1.0.0: Copying sources to build folder
bin2c/1.0.0: Building your package in C:\Users\guyadong\.conan\data\bin2c\1.0.0\_\_\build\63da998e3642b50bee33f4449826b2d623661505
bin2c/1.0.0: Generator txt created conanbuildinfo.txt
bin2c/1.0.0: Calling generate()
bin2c/1.0.0: Aggregating env generators
bin2c/1.0.0: Calling build()
bin2c/1.0.0:
bin2c/1.0.0: WARN: Build folder is dirty, removing it: C:\Users\guyadong\.conan\data\bin2c\1.0.0\_\_\build\63da998e3642b50bee33f4449826b2d623661505
bin2c/1.0.0: WARN: Using the new toolchains and generators without specifying a build profile (e.g: -pr:b=default) is discouraged and might cause failures and unexpected behavior
bin2c/1.0.0: ERROR: Package '63da998e3642b50bee33f4449826b2d623661505' build failed
bin2c/1.0.0: WARN: Build folder C:\Users\guyadong\.conan\data\bin2c\1.0.0\_\_\build\63da998e3642b50bee33f4449826b2d623661505\build
ERROR: bin2c/1.0.0: Error in build() method, line 32
        cmake.definitions["USE_BZ2"] = False
        AttributeError: 'CMake' object has no attribute 'definitions'

    def generate(self):
        tc = CMakeToolchain(self)
        tc.variables["USE_BZ2"] = False
        tc.generate()