def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def image_url(self, pixel_size=None):
        """
        Get the URL for the user icon in the desired pixel size, if it exists. If no
        size is supplied, give the URL for the full-size image.
        """
        if "profile" not in self._raw:
            return
        profile = self._raw["profile"]
        if (pixel_size):
            img_key = "image_%s" % pixel_size
            if img_key in profile:
                return profile[img_key]
        return profile[self._DEFAULT_IMAGE_KEY]