Get a file from a branch.

    Args:

        profile
            A profile generated from ``simplygithub.authentication.profile``.
            Such profiles tell this module (i) the ``repo`` to connect to,
            and (ii) the ``token`` to connect with.

        branch
            The name of a branch.

        file_path
            The path of the file to fetch.

    Returns:
        The (UTF-8 encoded) content of the file, as a string.

def get_file(profile, branch, file_path):
    """Get a file from a branch.

    Args:

        profile
            A profile generated from ``simplygithub.authentication.profile``.
            Such profiles tell this module (i) the ``repo`` to connect to,
            and (ii) the ``token`` to connect with.

        branch
            The name of a branch.

        file_path
            The path of the file to fetch.

    Returns:
        The (UTF-8 encoded) content of the file, as a string.

    """
    branch_sha = get_branch_sha(profile, branch)
    tree = get_files_in_branch(profile, branch_sha)
    match = None
    for item in tree:
        if item.get("path") == file_path:
            match = item
            break
    file_sha = match.get("sha")
    blob = blobs.get_blob(profile, file_sha)
    content = blob.get("content")
    decoded_content = b64decode(content)
    return decoded_content.decode("utf-8")