code: def main(conda_fname, pip_fname, compare=False):
      
      with open(conda_fname) as conda_fd:
          deps = yaml.safe_load(conda_fd)['dependencies']
  
      pip_deps = []
      for dep in deps:
          if isinstance(dep, str):
              conda_dep = conda_package_to_pip(dep)
              if conda_dep:
                  pip_deps.append(conda_dep)
          elif isinstance(dep, dict) and len(dep) == 1 and 'pip' in dep:
              pip_deps += dep['pip']
          else:
              raise ValueError('Unexpected dependency {}'.format(dep))
  
      pip_content = '\n'.join(pip_deps)
  
      if compare:
          with open(pip_fname) as pip_fd:
              return pip_content != pip_fd.read()
      else:
          with open(pip_fname, 'w') as pip_fd:
              pip_fd.write(pip_content)
          return False
docs: Generate the pip dependencies file from the conda file, or compare that
      they are synchronized (``compare=True``).
  
      Parameters
      ----------
      conda_fname : str
          Path to the conda file with dependencies (e.g. `environment.yml`).
      pip_fname : str
          Path to the pip file with dependencies (e.g. `requirements-dev.txt`).
      compare : bool, default False
          Whether to generate the pip file (``False``) or to compare if the
          pip file has been generated with this script and the last version
          of the conda file (``True``).
  
      Returns
      -------
      bool
          True if the comparison fails, False otherwise