import re


def extract_values(stderr):
    """
    Extracts values from ECHO statements as a dictionary. Values are strings.
    """
    result = {}
    pattern = re.compile(r'^ECHO: (.+) = (.+)$')
    for line in stderr.splitlines():
        m = pattern.search(line)
        if m:
            result[m.group(1)] = m.group(2)
    return result