# Source code for opentelemetry.trace.propagation

    # Copyright The OpenTelemetry Authors
    # SPDX-License-Identifier: Apache-2.0

    from opentelemetry.context import create_key, get_value, set_value
    from opentelemetry.context.context import Context
    from opentelemetry.trace.span import INVALID_SPAN, Span

    SPAN_KEY = "current-span"
    _SPAN_KEY = create_key("current-span")

    def set_span_in_context(span: Span, context: Context | None = None) -> Context:
        """Set the span in the given context.

        Args:
            span: The Span to set.
            context: a Context object. if one is not passed, the
                default current context is used instead.
        """
        ctx = set_value(_SPAN_KEY, span, context=context)
        return ctx

    def get_current_span(context: Context | None = None) -> Span:
        """Retrieve the current span.

        Args:
            context: A Context object. If one is not passed, the
                default current context is used instead.

        Returns:
            The Span set in the context if it exists. INVALID_SPAN otherwise.
        """
        span = get_value(_SPAN_KEY, context=context)
        if span is None or not isinstance(span, Span):
            return INVALID_SPAN
        return span