import re


def only_words(text):
    """
    Only Words - Discard Numbers.

    Parameters
    ----------
        text: str
            Text selected to apply transformation

    Examples:
    ---------
    ```python
    sentence="the world population has grown from 1650 million to 6000 million"
    only_numbers(sentence)
        >>> '1650 6000'
    ```
    """
    line = re.findall(r'\b[^\d\W]+\b', text)
    return " ".join(line)