lic.py

import pkg_resources

def get_pkg_license(pkgname):
    """
    Given a package reference (as from requirements.txt),
    return license listed in package metadata.
    NOTE: This function does no error checking and is for
    demonstration purposes only.
    """
    pkgs = pkg_resources.require(pkgname)
    pkg = pkgs[0]
    for line in pkg.get_metadata_lines('PKG-INFO'):
        (k, v) = line.split(': ', 1)
        if k == "License":
            return v
    return None

for w in pkg_resources.working_set:
    try:
        print w, get_pkg_license(str(w).split(" ")[0])
    except:
        print "UNKNOWN"