CreatePullRequest.
        [Preview API] Create a pull request.
        :param :class:`<GitPullRequest> <azure.devops.v5_1.git.models.GitPullRequest>` git_pull_request_to_create: The pull request to create.
        :param str repository_id: The repository ID of the pull request's target branch.
        :param str project: Project ID or project name
        :param bool supports_iterations: If true, subsequent pushes to the pull request will be individually reviewable. Set this to false for large pull requests for performance reasons if this functionality is not needed.
        :rtype: :class:`<GitPullRequest> <azure.devops.v5_1.git.models.GitPullRequest>`

def create_pull_request(self, git_pull_request_to_create, repository_id, project=None, supports_iterations=None):
        """CreatePullRequest.
        [Preview API] Create a pull request.
        :param :class:`<GitPullRequest> <azure.devops.v5_1.git.models.GitPullRequest>` git_pull_request_to_create: The pull request to create.
        :param str repository_id: The repository ID of the pull request's target branch.
        :param str project: Project ID or project name
        :param bool supports_iterations: If true, subsequent pushes to the pull request will be individually reviewable. Set this to false for large pull requests for performance reasons if this functionality is not needed.
        :rtype: :class:`<GitPullRequest> <azure.devops.v5_1.git.models.GitPullRequest>`
        """
        route_values = {}
        if project is not None:
            route_values['project'] = self._serialize.url('project', project, 'str')
        if repository_id is not None:
            route_values['repositoryId'] = self._serialize.url('repository_id', repository_id, 'str')
        query_parameters = {}
        if supports_iterations is not None:
            query_parameters['supportsIterations'] = self._serialize.query('supports_iterations', supports_iterations, 'bool')
        content = self._serialize.body(git_pull_request_to_create, 'GitPullRequest')
        response = self._send(http_method='POST',
                              location_id='9946fd70-0d40-406e-b686-b4744cbbcc37',
                              version='5.1-preview.1',
                              route_values=route_values,
                              query_parameters=query_parameters,
                              content=content)
        return self._deserialize('GitPullRequest', response)