title: SQLAlchemy ORM check if column is a foreign_key
body: <p>Hi I was wondering if anyone knows of the most efficient way to find out if a column has a foreignKey relationship or not.</p>
  
  
  
  <pre class="lang-python prettyprint-override"><code>class StudentIntendCourse(DeclarativeBase):
      __tablename__ = 'studentIntendCourse'
      id = Column(Integer, primary_key=True)
      studentID = Column('studentID',Integer,ForeignKey('student.id'))
      courseID = Column('courseID',Integer,ForeignKey('course.id'))
      course = relationship("Course",backref="studentIntendedCourses")
  </code></pre>
  
  <p>I would like to find out if is_foreign_key(StudentIntendCourse.studentID)?</p>